This chapter summarizes the research conducted in this dissertation, including its contributions as well as limitation.

7.0. Summary

The goal of this dissertation is to explore effective ways of formally approaching Chinese morpho-syntactic interface in a phrase structure grammar.  This research has led to the following results:  (i) the design of a Chinese grammar, namely CPSG95, which enables flexible coordination and interaction of morphology and syntax;  (ii) the solutions proposed in CPSG95 to a series of long-standing problems at the Chinese morpho-syntactic interface.

CPSG95 was designed in the general framework of HPSG (Pollard and Sag 1987, 1994).  The sign-based mono-stratal design from HPSG demonstrates the advantage in being capable of accommodating and accessing information of different components of a grammar.  One crucial feature of CPSG95 is its introduction of morphology expectation feature structures and the corresponding morphological PS rules into HPSG.  As a result, CPSG95 has been demonstrated to provide a favorable environment for solving morpho-syntactic interface problems.

Three types of morpho-syntactic interface problems have been studied extensively: (i) the segmentation ambiguity in Chinese word identification;  (ii) Chinese separable verbs, a borderline problem between compounding and syntax; and (iii) borderline phenomena between derivation morphology and syntax.

In the context of the CPSG95 design, the segmentation ambiguity is no longer a problem as morphology and syntax are designed system internally in the grammar to support morpho-syntactic parsing based on non-deterministic tokenization (W. Li 1997, 2000).  In other words, the design of CPSG95 itself entails an adequate solution to this long-standing problem, a problem which has been a central topic in Chinese NLP for the last two decades.  This is made possible because the access to a full grammar including both morphology and syntax is available in the integrated process of Chinese parsing and word identification while traditional word segmenters can at best access partial grammar knowledge.[1]

The second problem involves an interesting case between compounding and syntax:  different types of Chinese separable verbs demonstrate various degrees of separability in syntax while all these verbs, when used contiguously, are part of Chinese verb vocabulary.  For each type of separable verbs, arguments were presented for the proposed linguistic analysis and a solution to the problem was then formulated in CPSG95 based on the analysis.  All the proposed solutions provide a way of capturing the link between the separated use and the contiguous use of the separable verb phenomena.  They are shown to be better solutions than previous approaches in the literature which either cannot link the separated use and the contiguous use in the analysis or suffer from being not formal.

The third problem at the interface of derivation and syntax involves two issues: (i) a considerable amount of ‘quasi-affix’ data, and (ii) the intriguing case of zhe-suffixation which demonstrates an unusual combination of a phrase with a bound morpheme.  A generic analysis of Chinese derivation has been proposed in CPSG95.  This analysis has been demonstrated to be also effective in handling both quasi-affixation and zhe-affixation.

7.1. Contributions

The specific contributions are reflected in the study of the following five topics, each constituting a chapter.

On the topic of the Role of Grammar, the investigation leads to the central argument that knowledge from both morphology and syntax is required to properly handle the major types of morpho-syntactic interface problems.  This establishes the foundation for the general design of CPSG95 as consisting of morphology and syntax in one grammar formalism.

An in-depth study has been conducted in the area of the segmentation ambiguity in Chinese word identification.  The most important discovery from the study is that the disambiguation involves the analysis of the entire input string.  This means that the availability of a grammar is key to the solution of this problem.  A natural solution to this problem is the use of grammatical analysis to resolve, and/or prepare the basis for resolving, the segmentation ambiguity.

On the topic of the Design of CPSG95, a mono-stratal Chinese phrase structure grammar has been established in the spirit of the HPSG theory.  Components of a grammar such as morphology, syntax and semantics are all accommodated in distinct features of a sign.  CPSG95 is designed to provide a framework and means for formalizing the analysis of the linguistic problems at the morpho-syntactic interface.

The essential part of this work is the design of expectation feature structures.  Expectation feature structures are generalized from the HPSG feature structures for syntactic subcategorization and modification.  One characteristic of the CPSG95 structural expectation is the design of morphological expectation features to incorporate Chinese productive derivation, which covers a wide range of linguistic phenomena in Chinese word formation.

In order to meet the requirements induced by introducing morphology into the general grammar and by accommodating linguistic characteristics of Chinese, modifications from the standard HPSG are proposed in CPSG95.  The rationale and arguments for these modifications have been presented.  The design of CPSG95 is demonstrated to be a successful application of HPSG in the study of Chinese morpho-syntactic phenomena.

On the topic of Defining the Chinese Word, efforts have been made to reach a better understanding of Chinese wordhood in theory, methodology and formalization.

The theoretical inquiry follows the insight from Di Sciullo and Williams (1987) and Lü (1989).  Two notions of word, namely grammar word and vocabulary word, have been examined and distinguished.  While vocabulary word is easy to define once a lexicon is given, the object for linguistic study and generalization is actually grammar word.  Unfortunately, as there is a considerable amount of borderline phenomena between Chinese morphology and syntax, no precise definition of Chinese grammar word has been available across systems.  Therefore, an argument in favor of the system-internal wordhood definition and interface coordination within a grammar has been made.  This leads to a case-by-case approach to the analysis of specific Chinese morpho-syntactic interface problems.

On the other hand, three useful wordhood judgment methods have also been proposed as a complementary means to the case-by-case analysis.  These methods are (i) syntactic process test involving passivization and topicalization; (ii) keyword based judgment patterns for verbs, and (iii) a general expansion test named X-insertion.  These methods are demonstrated to be fairly operational and easy to apply.

In terms of formalization, a system-internal representation of word has been defined in CPSG95 feature structures.  This definition distinguishes a grammar word from both bound morphemes and syntactic constructions.  The formalization effort is necessary for the rigid study of Chinese morpho-syntactic problems and ensures the implementability of the solutions to these problems as proposed in the dissertation.

On the topic of Chinese Separable Verbs, the task is to coordinate the idiomatic nature of separable verbs and their separated uses in various syntactic patterns.

Since there are different degrees of ‘separability’ for different types of Chinese separable verbs, there is no uniform analysis which can handle all separable verbs properly.  A case-by-case study for each type of separable verbs has been conducted.  An essential part of this study is the arguments for the wordhood judgment for each type.  In the light of this judgment, CPSG95 provides formalized analyses of separable verbs which satisfy two criteria:  (i)  they all capture both structural and semantic aspects of the constructions at issue; (ii) they all provide a way of capturing the link between the separated use and contiguous use.

Finally, on the topic of Morpho-syntactic Interface Involving Derivation, a general approach to Chinese derivation has been proposed.  This approach not only enables us to handle quasi-affix phenomena, but is also flexible enough to provide an adequate treatment of the special problem in zhe-suffixation.

In the CPSG95 analysis, the affix serves as head of a derivative and can impose various constraints in the lexicon on its expected stem sign for the morphological expectation.  Coupled with only two PS rules formulated in the general grammar (Prefix PS Rule and Suffix PS Rule), it has been shown that various Chinese affixation phenomena can be captured equally well.  The PS rules ensure that all the lexical constraints be observed before the affix and the stem combine and that the output of derivation be a word.

As for the quasi-affixation problem, based on the observation that there is no fundamental structural difference between quasi-affixation and other affixation, a proper treatment of 'quasi-affixes' can be established in the same way as other affixes are handled in CPSG95; the individual difference in semantics is shown to be capturable in the lexicon.

The study of zhe-suffixation started with arguments for its analysis of VP+-zhe.  This is an unsolvable problem in any system which enforces sequential processing of morphology before syntax.  The solution which CPSG95 offers demonstrates the power of designing derivation morphology and syntax in a mono-stratal grammar.   With this novel design in modeling Chinese grammar, the CPSG95 general approach to derivation readily applies to the tough case of zhe-suffixation.  This is possible because of the ability of an affix in placing any lexicalized constraints, VP in this case, on the expected stem for morphological expectation.  In addition, the proposed lexicalized solution also captures the building of the semantic content for this morpho-syntactic borderline phenomenon.

7.2. Limitation

The major limitation of the work reported in this thesis lies in the following two aspects.

Limited by space, the thesis has only presented some sample formulation of typical affixes and quasi-affixes to demonstrate the proposed general approach to Chinese derivation morphology.  As many affixes/quasi-affixes have their distinctive semantic property, a reader who likes to experiment with this proposal in implementation still has to work out the technical details for each affix.  However, it is believed that the general strategy has been presented in sufficient details to allow for easy accommodation of individual aspects of an affix which have not been specifically addressed in the thesis.

Limited by the focus on a handful of major morpho-syntactic interface problems, the treatment of reduplication and unlisted proper names have not been listed as special topics for in-depth exploration.  They are only briefly discussed in Chapter II (Section 2.2) as cases of productive word formation for the need to involve syntax when they involve segmentation ambiguity at the boundaries.  However, they are also long-standing word identification problems which affect morpho-syntactic interface when the segmentation ambiguity is involved.  In particular, it is felt that the treatment of transliterated foreign names requires further research before a satisfactory solution can be found in the framework of CPSG95.[2]

7.3. Final Notes

This last section is used to place the research reported in this thesis in a larger context.

Chinese NLP has reached a new stage marked by the publication of Guo’s series of papers on Chinese tokenization (Guo 1997a,b,c,d, Guo 1998).  There are signs that the major research focus is being shifted from word segmentation to the grammar design and development.  In this process,  the morph-syntactic interface will remain a hot topic for quite some time to come.  The work on CPSG95 can be seen as one of the efforts in this direction.

The design of CPSG95, a formal grammar capable of representing both morphology and syntax in a uniform formalism, is one successful application of the modern linguistic theory HPSG in the area of Chinese  morpho-syntactic interface research.  However, this is by no means to claim that CPSG95 is the only or best framework to capture the morpho-syntactic problems.   This is only one approach which has been shown to be feasible and effective.  Other equally good or better approaches may exist.

In terms of future directions, constraints from semantics and discourse should be made available in the grammatical analysis.  In Chapter II (Section 2.4), we have seen problems whose ultimate solutions depend on the access to the semantic or discourse constraints.  It is believed that the sign-based mono-stratal design of CPSG95 will be extensible to accommodate these constraints.  However, this will require years of future research before they can be formally modeled and properly introduced into the grammar.

--------------------------

[1] As a matter of fact, the CPSG95 experiment shows that most segmentation ambiguity is resolved automatically as a by-product of morpho-syntactic parsing and the remaining ambiguity is embodied in the multiple syntactic trees as the results of the analysis.

[2] However, in the CPSG95 implementation, the problem of handling the Chinese person names, a special case of compounding, has been solved fairly satisfactorily.  The proposal is to use the surname as the head sign to expect the given name (of one or two characters) on its right to form potential full names.  As the right boundary of a person name is difficult to define without the support of sentential analysis, the conventional word segmenter frequently makes wrong segmentation in such cases.  In contrast, the approach implemented in CPSG95 is free from this problem because whether a potential name proposed by the surname ultimately survive as a proper name is decided by whether it contributes to a valid parse for the processed sentence.  In last few years, there has been rapid progress on proper name identification in the area of information extraction, called named entity tagging (MUC7 1998; Chen et al 1997).

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[Related]

PhD Thesis: Morpho-syntactic Interface in CPSG (cover page)

PhD Thesis: Chapter I Introduction

PhD Thesis: Chapter II Role of Grammar

PhD Thesis: Chapter III Design of CPSG95

PhD Thesis: Chapter IV Defining the Chinese Word

PhD Thesis: Chapter V Chinese Separable Verbs

PhD Thesis: Chapter VI Morpho-syntactic Interface Involving Derivation

PhD Thesis: Chapter VII Concluding Remarks

Overview of Natural Language Processing

Dr. Wei Li’s English Blog on NLP

6.0. Introduction

This chapter studies some challenging problems of Chinese derivation and its interface with syntax.  These problems have been a challenge to existing word segmenters; they are also long-standing problems for Chinese grammar research.

It is observed that a good number of signs have become more and more like affixes as the Chinese language develops.  Typical, indisputable examples include signs like the nominalizer 性 ‑xing (-ness) and the prefix 第 di- (-th).  While few people doubt the existence of affixes in Contemporary Chinese, there is no general agreement on the exact number of Chinese affixes, due to a considerable number of borderline cases often referred to as ‘quasi-affixes’ (类语缀 lei yu-zhui).[1]  It will be argued that the quasi-affixes belong to morphology and are structurally not different from other affixes.  The major difference between ‘quasi-affixes’ and the few generally honored (‘genuine’) affixes lies mainly in the following aspect.  The former retain some ‘solid’ meaning while the latter are more functionalized.  However, this does not prevent CPSG95 from providing a proper treatment of quasi-affixes in the same way as it handles other affixes.  It will be shown that the difference in semantics between affixes or quasi-affixes can be accommodated fairly easily in the CPSG95 lexicon.

Based on the examination of the common property of Chinese affixes and quasi-affixes, a general approach to Chinese derivation is proposed.  This approach not only enables us to handle quasi-affix phenomena, but is also flexible enough to provide an adequate treatment of a special problem in Chinese derivation, namely zhe-suffixation.  The affix status of 者 -zhe (-er) is generally acknowledged (classified as suffix in the authoritative books like Lü et al 1980):  it attaches to a verb sign and produces a word.  The peculiar aspect of this suffix is that the verb stem which it attaches to can be syntactically expanded.  In fact, there is significant amount of evidence for the argument that this suffix expects a VP as its stem (see 6.5 for evidence).   Since a VP is only formed in syntax and derivation is within the domain of morphology, this phenomenon presents a highly challenging case on how morphology should be interfaced properly to syntax.  The solution which is offered in CPSG95 demonstrates the power of designing morphology and syntax in an integrated grammar formalism.  In contrast, in any system which enforces sequential processing of derivation morphology before syntax - most traditional systems assume this, this is an unsolvable problem.  There does not seem to be a way of enabling partial output of syntactic analysis (i.e. VP) to feed back to some derivation rule in the preprocessing stage.

In Section 6.1, the general approach to Chinese derivation is proposed first.  Following this proposal, prefixation is illustrated in 6.2 and suffixation in 6.3.  Section 6.4 shows that this general approach to derivation applies equally well to the 'quasi-affix' phenomena.  Section 6.5 investigates the suffixation of -zhe (-er).  The analysis is based on the argument that this suffixation involves the combination VP+-zhe.  The specific solution following the CPSG95 general approach will be presented based on this analysis.

6.1. General Approach to Derivation

This section examines the property of Chinese affixes and proposes a corresponding general approach to Chinese derivation.  This serves as the basis for the specific solutions to be presented in the remaining sections to various problems in Chinese derivation.

It is fairly easy to observe that in Chinese derivation it is the affix which selects the stem, not the other way round.  For example, the suffix 性 -xing (‑ness) expects an adjective to produce an (abstract) noun.   Based on the examination of the behavior of a variety of Chinese affixes or quasi-affixes, the following generalization has been reached.  That is, an affix lexically expects a sign of category x, with possible additional constraints, to form a derived word of category y.   This generalization is believed to capture the common property shared by Chinese affixes/quasi-affixes.  It seems to account for all Chinese derivational data, including typical affixation, quasi-affixation (see 6.4) and the special case of zhe-suffixation (see 6.5).  So far no counter evidence has been found to challenge this generalization.

The observation and the generalization above support the argument that in a grammar which relies on lexicalized expectation feature structures to drive the building of structures, affixes, not the stems, should be selecting heads of the morphological structures.[2]   Leaving aside the non-productive affixation,[3] the general strategy to Chinese productive derivation is proposed as follows.  In the lexicon, the affix as head of derivative is encoded with the following derivation information:  (i) what type of stem (constraints) it expects;  (ii) where to look for the expected stem, on its right or left;  (iii) what type of (derived) word it leads to (category, semantics, etc.).  Based on this lexical information, CPSG95 has two PS rules in the general grammar for derivation:  one for prefixation, one for suffixation.[4]  These rules ensure that all the constraints be observed before an affix and a stem are combined.  They also determine that the output of derivation, i.e. the mother sign, be a word.

Along this line, the key to a lexicalized treatment of Chinese derivation is to determine the structural and semantic property of the derivative and to impose proper constraints on the expected stem.  The constraints on the expected stem can be lexically specified in the morphological expectation feature [PREFIXING] or [SUFFIXING] of the affix.  The property (category, syntactic expectation, semantics, etc.) of the derivative can also be encoded directly in the lexical entry of the affix, seen as the head of a derivational structure in the CPSG95 analysis.  This property information, as part of head features, will be percolated up when the derivation rules are applied.

In the remaining part of this chapter, it will be demonstrated how this proposed general approach is applied to each specific derivation problem.

6.2. Prefixation

The purpose of this section is to present the CPSG95 solution to Chinese prefixation.  This is done by formulating a sample lexical entry for the ordinal prefix 第 di- (-th) in CPSG95.  It will be shown how the lexical information drives the prefix rule in the general grammar for the derivational combination.

Thanks to the productivity of the prefix 第 di- (-th), the ordinal numeral is always a derived word from the cardinal numeral via the following rule, informally formulated in (6-1).

(6-1.) 第 di- + cardinal numeral --> ordinal numeral

第22条军规
di-      22      tiao    jun-gui
-th     22      CLA   military-rule
the 22-nd military rule (Catch-22)

第八个是铜像
di-      ba      ge      shi     tong-xiang
-th     eight  CLA   be      bronze-statue
The eighth is the bronze statue.

The basic function of the Chinese numeral, whether cardinal or ordinal,  is to combine with a classifier, as shown in the sample sentences above.

To capture this phenomenon, CPSG95 defines two subtypes for the category numeral [num], namely the [cardinal_num] and [ordinal_num].   The lexical entries of the prefix 第 di‑ (‑th) and the cardinal numeral 五 wu (five) are formulated in (6-2) and (6-3).  The prefix encodes the lexical expectation for the derivation 第 di- + [cardinal_num] ‑‑> [ordinal_num] plus the semantic composition of the combination.  Note that the constraint @numeral inherits all common property specified for the numeral macro.

As indicated before, prefixation in CPSG95 is handled by the Prefix PS Rule based on the lexical specification.  More specifically, it is driven by the lexical expectation encoded in [PREFIXING].  The prefix rule is formulated in (6-4).

Like all PS rules in CPSG95, whenever two adjacent signs satisfy all the constraints, this rule takes effect in combining them into a higher level sign in parsing.  For example, the prefix 第 di- (-th) and the sign 五 wu (five) will be combined into the sign as shown in (6-5).

The combination of 第五 di+wu in (6-5) demonstrates how the morphological structure is built in the CPSG95 approach to Chinese prefixation.

6.3. Suffixation

Like prefixation, the Suffix PS Rule for suffixation is driven by the lexically encoded expectation in [SUFFIXING].  Parallel to the Prefix PS Rule, the suffix rule is formulated in (6-6).

With this PS rule in hand, all that is needed is to capture the individual derivational constraint in the lexical entries of the suffixes at issue.  For example, the suffix 性 -xing (-ness) changes an adjective or verb into an abstract noun:  A/V + ‑xing  ‑‑> N.  This information is contained in the formulation of the suffix 性 –xing (-ness) in the CPSG95 lexicon, as shown in (6-7).

Note that abstract nouns are uncountable, hence the call to the uncountable_noun macro to inherit the common property of uncountable nouns.[5]

Suppose the suffix 性 -xing (-ness) appears immediately after the adjective 实用 shi-yong (practical) formulated in (6-8), the suffix PS rule will combine them into a noun, as  shown in (6-9).

The combination of 实用性 shi-yong+xing in (6-9) demonstrates how the morphological structure is built in the CPSG95 approach to Chinese suffixation.

6.4. Quasi-affixes

The purpose of this section is to propose an adequate treatment of the quasi-affix phenomena in Chinese.  This is an area which has not received enough investigation in the field of Chinese NLP.  Few Chinese NLP systems demonstrate where and how to handle these quasi-affixes.

To achieve the purpose, typical examples of ‘quasi-affixes’ are presented and compared with some ‘genuine’ affixes.  The comparison highlights the general property shared by both 'quasi-affixes' and other affixes and also shows their differences.  Based on this study, it is found to be a feasible proposal to treat quasi-affixes within the derivation morphology of CPSG95.  The proposed solution will be presented by demonstrating how a typical quasi-affix is represented in CPSG95 and how the general affix rules can work with the lexical entries of 'quasi-affixes' as well.

The tables in (6-10) and (6-11) list some representative quasi-affixes in Chinese.

(6-10.)         Table for sample quasi-prefixes

(6-11.)         Table for sample quasi-suffixes

Compare the above quasi-affixes with the few widely acknowledged affixes like 性 -xing (-ness) and 第 di- (-th), it is fairly easy to observe that the property as generalized in Section 6.1 is shared by both affixes and quasi-affixes.  That is, in all cases of the combination, the affix or quasi-affix expects a sign of category x, with possible additional constraints, either on the right or on the left to form a derived word of category y (y may be equal to x).  For example, the quasi-prefix 自 zi- (self-) expects a transitive verb to produce an intransitive verb, etc.  This property supports the following two points of view:  (i) the affix or quasi-affix is the selecting head of the combination;  (ii) both types of combination (affixation) should be properly contained in morphology since the output is always a word (derivative).

In terms of difference, it is observed that there are different degrees of the functionalization of the meaning between quasi-affixes and other affixes.  For example, the nominalizer 性 -xing (‑ness) seems to be semantically more functionalized than the quasi-suffix 盲 -mang (blind-man, person who has little knowledge of).  In the case of 性 -xing (-ness), there is believed to be little semantic contribution from the affix.  But in cases of affixation by quasi-affixes, the semantic contribution of the affixes is non-trivial, and it must be ensured that proper semantics be built based on semantic compositionality of both the stem and the affix.

Except for the different degrees of semantic abstractness, there is no essential grammatical difference observed between quasi-affixes and the few widely accepted affixes.  As the semantic variation can be easily accommodated in the lexicon, nothing needs to be changed in the  general approach to Chinese derivation as described before.  The text below demonstrates how the quasi-affix phenomena are handled in CPSG95, using a sample quasi-affix to show the derivation.

The quasi-prefix to examine is 相 xiang- (each other).  It is used before a mono-syllabic transitive verb, making it an intransitive verb: 相 xiang- + Vt (monosyllabic) ‑‑> Vi.  More precisely, the syntactic object of the transitive verb is morphologically satisfied so that the derivative becomes an intransitive verb.

Unlike the original verb, the verb derived via xiang-prefixation requires a plural subject, as shown in (6-12).  This is a linguistically interesting phenomenon.  In a sense, it is a version of subject-predicate agreement in Chinese.

(6-12.) (a)    他们相爱过。
ta-men         xiang-         ai       guo
they            each-other   love    GUO
They used to love each other.

(b)      他爱过。
ta       ai       guo
he      love    GUO.
He used to love (someone).

(b) *   他相爱过。
ta       xiang-         ai       guo
he      each-other   love    GUO.

This number agreement can help decode the plural semantics of the subject noun as shown in the first sentence (6-13a) in the following group.  Sentence (6-13a) illustrates a common, number-underspecified case where the NP has no plural marker.  This contrasts with (6-13b) which includes a plural marker 们 men (-s), and with (6-13c) which resorts to the use of a numeral-classifier construction.

(6-13.) (a)     孩子相爱了。
hai-zi           xiang-         ai       le
child           each-other   love    LE
The children have fallen in love with each other.

(b)      孩子们相爱了。
hai-zi men   xiang-         ai       le
child  PLU   each-other   love    LE
The children have fallen in love with each other.

(c)      两个孩子相爱了。
liang ge      hai-zi           xiang-         ai       le
two    CLA   child           each-other   love    LE
The two children have fallen in love with each other.

Following the practice for number agreement in HPSG, the agreement can be captured by enforcing an additional plural constraint on the subject expectation [SUBJ | SIGN | CONTENT | INDEX | NUMBER plural], as shown in the formulation of the lexical entry for 相 xiang- (each other) in (6-14) below.

As shown above, the affixation also necessitates corresponding modification of the semantics in the argument structure:  the first argument is equal to the second via index [2].[6]  Note that the notation [ ], or more accurately, the most general feature structure, is used as a place holder.  For example, HANZI <[ ]> stands for the constraint of a mono-hanzi sign.  Another thing worth noticing is that the derivative requires that a subject must appear before it.  In other words, the subject expectation becomes obligatory.  This is based on the fact that this derived verb cannot stand by itself in syntax, unlike most original verbs in Chinese, say 爱 ai (love), whose subject expectation is optional.

With the lexical entries for the quasi-affixes taking care of the differences in the building of semantics, there is no need for any modification of the CPSG95 PS rules.  For example, the prefix 相 xiang- (each other) and the verb 爱 ai (love) formulated in (6-15) will be combined into the derivative 相爱 xiang-ai (love each other) shown in (6-16) via the Prefix PS Rule.

In summary, the proposed approach to Chinese derivation is effective in handling quasi-affixes as well.  The general grammar rules for derivation remain unchanged while lexical constraints are accommodated in the lexicon.  This demonstrates the advantages of the lexicalized design for grammar development.

6.5. Suffix 者 zhe (-er)

This section analyzes zhe-suffixation, a highly challenging  case at the interface between morphology and syntax.  This is believed to be an unsolvable problem as long as a system is based on the sequential processing of derivation morphology and syntax.  The solution to be proposed in this section is based on the argument that this suffixation is a combination of VP+zhe.

The suffix 者 zhe (-er, person) is a very productive bound morpheme.   It is often compared to the English suffix ‑er or ‑or, as seen in the pairs in (6-17).

(6-17.)
工作 gong-zuo (work)      工作者 [gong-zuo]-zhe (work‑er)
劳动 lao-dong (labor)       劳动者 [lao-dong]-zhe (labor-er)
学习 xue-xi (learn)           学习者 [xue-xi]-zhe (learn-er);.

But 者 ‑zhe is not an ordinary suffix;  it belongs to the category of so-called ‘phrasal affix’,[7] with very different characteristics than the English counterpart.  Although the output of the zhe-suffixation is a word, the input is a VP, not a lexical V.  In other words, it combines with a VP and produces a lexical N:  VP+zhe --> N.   The arguments to be presented below support this analysis.

The first thing is to demonstrate the word status of zhe‑suffixation.  This is fairly straightforward:  there are no observed facts to show that the zhe-derivative is different from other lexical nouns in the syntactic distribution.  For example, like other lexical nouns, the derivative can combine with an optional classifier construction to form a noun phrase.   Compare the following pairs of examples in (6-18) and (6-19).

(6-18.) (a)    两名违反这项规定者
liang  ming [[wei-fan      zhe    xiang gui-ding]     -zhe]
two    CLA   violate         this    CLA   regulation   -er
two persons who have violated this regulation

(b)    两名学生
liang  ming xue-sheng
two    CLA   student
two students

(6-19.) (a)    他是一位优秀工作者
ta       shi     yi       wei    you-xiu        [[gong-zuo]   -zhe]
he      be      one    CLA   excellent      work           -er
He is an excellent worker.

(b)    他是一位优秀工人。
ta       shi     yi       wei    you-xiu        gong-ren
he      be      one    CLA   excellent      worker
He is an excellent worker.

The next thing is to demonstrate the phrasal nature of the ‘stem’.[8]   The stem is judged as a VP because it can be freely expanded by syntactical complements or modifiers without changing the morphological relationship between the stem and the suffix, as shown in (6‑20) below.  (6-20a) involves a modifier (努力 nu-li) before the head verb.  The verb stem in (6-20b) and (6-20c) is a transitive VP consisting of a verb and an NP object.

(6-20.) (a)    努力工作者
[nu-li  gong-zuo]     -zhe
hard  work           ‑er
hard-worker, person who works hard

(b)      学习鲁迅者
[xue-xi         Lu Xun]       -zhe
learn           Lu Xun       -er
person who is learning from Lu Xun

(c)      违反这项规定者
[wei-fan       zhe    xiang           gui-ding]      -zhe
violate         this    CLA   regulation   -er
person who violates this rule

More examples with the head verb 雇 gu (employ) are given in (6-21), with the last two expressions involving passivized VP.

(6-21.)(a)    雇者
gu-zhe
employ-er

(b)      雇人者
[gu               ren]             -zhe
employ        person         -er
those who employ people, employer/recruiter

(c)      被雇者
[bei gu]                  -zhe
[be-employed]       -er
employee

(d)      被人雇者
[bei    ren              gu]               -zhe
by      person         employ        -er
those who are employed by (other) people

In fact, the stem VP is semantically equivalent to a relative clause.   A Chinese relative clause is normally expressed in the form of a DE-phrase: VP+de+N (Xue 1991).  In other words, 者 ‑zhe embodies functions of two signs, an N (‘person’, by default) and a relative clause introducer de, something like English one that + VP (or person who + VP).[9]  Compare the two examples in (6-22) and (6-23) with the same meaning - the expression in (6-23) is more colloquial than the first in (6-22) which uses the suffix 者‑zhe.

(6-22.) 违反规定者，处以罚款。
wei-fan        gui-ding       zhe,            chu-yi                   fa-kuan
violate         regulation   one that      punish-by   fine

Those who violate the regulations will be punished by fines.

(6-23.) 违反规定的人，处以罚款。
wei-fan        gui-ding       de      ren,             chu-yi          fa-kuan
violate         regulation   DE     person         punish-by   fine
Those who violate the regulations will be punished by fines.

On further examination, it is found that VPs with attached aspect markers combine with the suffix 者 -zhe with difficulty, as seen in the following examples.

(6-24.) (a)    违反规定者
wei-fan        gui-ding       zhe
violate         regulation   -er
Those who violate the regulations

(b) ?  违反了规定者
wei-fan        le       gui-ding       zhe
violate         LE     regulation   one that

This means that some further constraint may be necessary in order to prevent the grammar from producing strings like (6-24b).  If CPSG95 is only used for parsing, such a constraint is not absolutely necessary because, in normal Chinese text, such input is almost never seen.  Since CPSG95 is intended to be procedure-neutral, for use in both parsing and generation, the further constraint is desirable.

This constraint is in fact not an isolated phenomenon in Chinese grammar.  In syntax, the constraint is commonly required when the VP is not in the predicate position.[10]  For example, when a verb, say 喜欢 xi-huan (like), or a preposition, say 为了 wei-le (in order to), subcategorizes for a VP as a complement, it actually expects a VP with no aspect markers attached.   The following pair of sentences demonstrates this point.

(6-25.) (a)    我喜欢打篮球。
wo     xi-huan       da      lan-qiu.
I         like              play   basket-ball
I like playing basket-ball.

(b) * 我喜欢打了篮球。
wo     xi-huan       da      le       lan-qiu
I         like              play   LE     basket-ball

To accommodate such common constraint requirement in both Chinese morphology and syntax, a binary feature [FINITE] is designed for Chinese verbs in CPSG95.  In the lexicon, this feature is under-specified for each Chinese verb, i.e. [FINITE bin].  When an aspect marker 了着过 le/zhe/guo combines with the verb, this feature is unified to be [FINITE plus].  We can then enforce the required constraint [FINITE minus] in the morphological expectation or syntactic expectation to prevent aspected VP from appearing in a position expecting a non-predicate un-aspected  VP.

Based on the above analysis, the lexical entry of the suffix 者 –zhe is formulated in (6-26).  Note the notation for the macro with parameter (placed in parentheses) @common_noun(名|位|个).  This macro represents the following information.  The derivative is like any other common noun, it inherits the common property;  it can combine with an optional classifier construction using the classifier 名 ming or 位  wei or 个 ge.[11]

As seen, the VP expectation is realized by using the macro constraint @vp.  The semantics of the derivative is [np_semantics], an instance of -er with restriction from the event of VP, represented by [2].  The index [1] ensures that whatever is expected as a subject by the VP, which has no chances to be satisfied syntactically in this case, is semantically identical to this noun.[12]  In other words, this derived noun semantically fills an argument slot held by the subject in the VP semantics [v_content].  In the active case, say, 雇人者 [gu ren]–zhe (‘person who employs people’), the subject is the first argument, i.e. the index of this noun is the logical subject of employ.  However, when the VP is in passive, say, 被人雇者 [bei ren gu]‑zhe (‘person who is employed by other people’), the subject expected by the VP fills the second argument, i.e. the noun in this case is the logical object of the VP.  It is believed that this is the desired result for the semantic composition of zhe-derivation.

With the lexical expectation of the suffix as the basis, the general Suffix PS Rule is ready to work.  Remember that there is nothing restricting the input stem to the derivation in either of the derivation rules, formulated in (6-4) and (6-6) before.  In CPSG95, this is not considered part of the general grammar but rather a lexical property of the head affix.  It is up to the affix to decide what constraints such as category, wordhood status, semantic constraint, etc., to impose on the expected stem to produce a derivative.  In most cases of derivation, the input status of the stem is a word, but now we have an intricate case where the suffix zhe (-er) expects a verb phrase for derivation.  The general property for all cases of derivation is that regardless of the input, the output of derivation (as well as any other types of morphology) is always a word.

Before demonstrating by examples how zhe-derivation is implemented, there is a need to address the configurational constraints of CPSG95.  This is an important factor in realizing the flexible interaction between morphology and syntax as required in this case.

In all HPSG-style grammars, some type of configurational constraint is in place to ensure the proper order of rule application.  A typical constraint is that the subject rule should apply after the object rule.  This is implemented in CPSG95 by imposing the constraint in the subject PS rule that the head daughter must be a phrase and by imposing the constraint in the object PS rule that the subject of the head daughter may not be satisfied.[13]

Since derivation morphology and syntax are designed in the same framework in CPSG95, constraints are called for to ensure the ordering of rule application between morphological PS rules and syntactic PS rules as well.  In general, morphological rules apply before syntactic rules.  However, if this constraint is made absolute, to the extent that that all morphological rules must apply before all syntactic rules, we in effect make morphology and syntax two independent, successive modules, just like the case for traditional systems.  The grammar will then lose the power of flexible interaction between morphology and syntax and cannot handle cases like zhe-derivation.  However, this is not a problem in CPSG95.

The proposed constraint regulating the rule application order between morphological PS rules and syntactic PS rules is as follows.  Only when a sign has both obligatory morphological expectation and syntactic expectation will CPSG95 have constraints ensuring that the morphological rule apply first.  For example, as formulated in (6-14) before, the sign 相 xiang- (each other) has both morphological expectation in [PREFIXING] as a bound morpheme and syntactic expectation for the subject in [SUBJ] as (head of) derivative.  If the input string is 他们相爱  ta-men (they) xiang- (each other) ai (love), the prefix rule will first combine 相 xiang- (each other) and the stem 爱 ai (love) before the subject rule can apply.  The result is the expected structure embodying the results of both morphological analysis and syntactic analysis, [ta-men [xiang- ai]].  This constraint is implemented by specifying in all syntactic PS rules that the head daughter cannot have obligatory morphological expectation yet to be satisfied.  It effectively prevents a bound morpheme from being used as a constituent in syntax.   It should be emphasized that this constraint in the general grammar does not prohibit a bound morpheme from combining with any types of sign;  such constraints are only lexically decided in the expectation feature of the affix.

The following text shows step by step the CPSG95 solution to the problem of zhe-derivation.  The chosen example is the derivation for the derived noun 违法规定者 [[wei-fan gui-ding]-zhe]  ‘persons violating (the) regulation’.  The lexical sign of the suffix 者 -zhe (-er) has already been formulated in (6-26) before.  The words 违反 wei-fan (violate) and 规定 gui-ding (regulation) in the CPSG95 lexicon are shown in (6-27) and (6-28) respectively.

Note that all common nouns, specified as @common_noun, in the lexicon have the following INDEX features [PERSON 3, NUMBER number], i.e. third person with unspecified number.  As for the feature [GENDER], it is encoded in the noun itself with one of the following [male], [female], [have_gender], [no_gender] or unspecified as [gender].   The corresponding sort hierarchy is: [gender] consists of sub-sorts [no_gender] and [have_gender];  and [have_gender] is sub-typed into [male] and [female].  Of course, 规定 gui-ding (regulation) is lexically specified as [GENDER no_gender].

The following is the VP built by the object PS rule in the CPSG95 syntax.  As seen, the building of the semantics follows the practice in HPSG, with the argument slots filled by the [INDEX] feature of the subject and object.  In this VP case, [ARG2] has been realized.

The VP result in (6-29) and the suffix 者 –zhe will combine into the expected derived noun via the Suffix PS Rule, as shown in (6-30).

To summarize, it is the integrated model of derivational morphology and syntax in CPSG95 that makes the above analysis implementable.  Without the integration, there is no way that a suffix is allowed to expect a phrasal stem.[14]  The lexicalist approach adopted in CPSG95 facilitates the capturing of the individual feature of the phrase expectation for the few individual affixes like 者 -zhe. This enables the general PS rules for derivation in CPSG95 to be applicable to both typical cases of affixation and special cases of affixation.

6.6. Summary

This chapter has investigated some representative phenomena of Chinese derivation and their interface to syntax.  The solutions to these problems have been presented based on the arguments for the analysis.

The key to a lexicalized treatment of Chinese derivation is to determine the structural and semantic property of the derivative and to impose proper constraints on the expected stem.  The constraints on the expected stem are lexically specified in the corresponding morphological expectation feature structure of the affix.  The property of the derivative is also lexically encoded in the affix, seen as head of derivational structure in the CPSG95 analysis.  This property information will be percolated up when the derivation rules are applied.  These rules ensure that the output of derivation is a word.  It has been shown that this approach applies equally well to derivation via ‘quasi-affixes’ and the tough case of zhe-suffixation as well.

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[1] Some linguists (e.g. Li and Thompson 1981) hold the view that Chinese has only a few affixes;  others (e.g. Chao 1968) believe that the inventory of Chinese affixes should be extended to include quasi-affixes.  Interestingly, the sign lei (quasi-, original sense ‘class’) itself is a quasi-prefix in Chinese.  Phenomena similar to Chinese quasi-affixes, called ‘semi-affixes’ or ‘Affixoide’, also exist in German morphology (Riehemann 1998).

[2] This is similar to the practice in many grammars, including HPSG, that a functional sign preposition is the selecting head of the corresponding syntactic structure, namely Prepositional Phrase.

[3] Those affixes which are not or no longer productive, e.g. lao‑ (original meaning ‘old’) in lao‑hu (tiger) and lao‑shu (mouse),  are not a problem.  The corresponding derived words are simply listed in the CPSG95 lexicon.

[4] The CPSG95 phrase-structural approach to Chinese productive derivation was inspired by the implementation in HPSG of a word-syntactic approach in Krieger (1994).  Similar practice is also seen in Selkirk (1982), Riehemann (1993) and Kathol (1999) in an effort to explore alternative approaches than the lexical rule approach to morphology.

[5] The major common property is reflected in two aspects, formulated in the macro definition of uncountable_noun in CPSG95.  First, there is value setting for the [NUMBER] feature, i.e. [CONTENT|INDEX|NUMBER no_number].  The CPSG95 sort hierarchy for the type [number] is defined as {a_number, no_number} where [a_number] is further sub-typed into {singular, plural}.  [NUMBER no_number] applies to uncountable nouns while [NUMBER a_number] is used for countable noun where the plurality is yet to be decided (i.e. under-specified for plurality).  Second, based on the syntactic difference between Chinese countable nouns and uncountable nouns, the classifier expected by uncountable nouns is exclusively zhong (kind/sort of).  That is, uncountable nouns may only combine with a preceding classifier construction using the classifier zhong.

[6] For time being, the subtle difference in semantics between pairs like We love ourselves and We love each other is not represented in the content.  It requires a more elaborate system of semantics to reflect the nuance.  The elaboration of semantics is left for future research.

[7] Some linguists (e.g. Z. Lu 1957; Lü et al 1980; Lü 1989; Dai 1993) have briefly introduced the notion of ‘phrasal affix’ in Chinese.  Lü further indicates that these ‘phrasal affixes’ are a distinctive characteristic of the Chinese grammar.

[8] The English possessive morpheme ‘s is arguably a suffix which expects an NP instead of a lexical noun as its stem:  NP + -’s.  Unlike VP + -zhe, the result of this NP + -‘s combination is generally regarded as a phrase, not a word.  In this sense, ‘s seems to be closer to a functional word, similar to a preposition or postposition, than to a suffix.

[9] Chinese zhe-suffixation is somewhat like the English phenomenon of what-clause (in ‘what he likes is not what interests her’). ‘What’ in this use also embodies functions of two signs that which. But the English what-clause functions as an NP, but VP+zhe forms a lexical N.

[10] It is generally agreed in the circle of Chinese grammar research that Chinese predicate (or finite) verbs have aspect distinction, using or not using aspect markers.  This is in contrast to English where both finite and non-finite verbs have aspect distinction but only finite verbs are tensed.

[11] It is generally agreed that each Chinese common noun may only combine with a classifier construction using a specific set of classifiers.  This classifier specification is generally regarded as lexical, idiosyncratic information of nouns (Lü et al 1980).  Using the macro with the classifier parameter follows this general idea.  It is worth noticing that the lexical formulation for -zhe (-er) in CPSG95 does not rely on any specific NP analysis chosen in syntax, except that the classifier specification should be placed under the entry for nouns (or derived nouns).

[12] The proposal in building the semantics for the zhe-derivative is based on ideas similar to the assumption adopted for the complement control in HPSG that ‘the fundamental mechanism of control was coindexing between the unexpressed subject of an unsaturated complement and its controler’ (Pollard and Sag 1994:282).

[13] If the object expectation is obligatory, this constraint ensures the priority of the object rule over the subject rule in application, building the desirable structure [S [V O]] instead of [[S V] O].  This is because, a verb with obligatory object yet to be satisfied is by definition not a phrase.  If the object expectation is optional, the order of rule application is still in effect although the lexical V in this scenario does not violate the phrase definition.  There are two cases for this situation.  In case one, the object O happens to occur in the input string.  The subject PS rule will tentatively combine S and V via the subject rule, but it can go no further.  This is because the object rule cannot apply after the subject rule, due to the constraint in the object rule that the head cannot have a satisfied subject.  The successful parse will only build the expected structure [S [V O]].  In case two, the object O does not appear in the input string.  Then the tentative combination [S V] built by the subject rule becomes the final parse.

[14] For example, if the lexical rule approach were adopted for derivation, this problem could not be solved.

[Related]

PhD Thesis: Morpho-syntactic Interface in CPSG (cover page)

PhD Thesis: Chapter I Introduction

PhD Thesis: Chapter II Role of Grammar

PhD Thesis: Chapter III Design of CPSG95

PhD Thesis: Chapter IV Defining the Chinese Word

PhD Thesis: Chapter V Chinese Separable Verbs

PhD Thesis: Chapter VI Morpho-syntactic Interface Involving Derivation

PhD Thesis: Chapter VII Concluding Remarks

Overview of Natural Language Processing

Dr. Wei Li’s English Blog on NLP

5.0. Introduction

This chapter investigates the phenomena usually referred to as separable verbs (离合动词 lihe dongci) in the form V+X.  Separable verbs constitute a significant portion of Chinese verb vocabulary.[1]  These idiomatic combinations seem to show dual status (Z. Lu 1957; L. Li 1990).  When V+X is not separated, it is like an ordinary verb.   When V is separated from X, it seems to be more like a phrasal combination.  The co-existence of both the separated use and contiguous use for these constructions is recognized as a long-standing problem at the interface of Chinese morphology and syntax (L. Wang 1955;  Z. Lu 1957; Chao 1968; Lü 1989; Lin 1983;  Q. Li 1983; L. Li 1990; Shi 1992; Dai 1993; Zhao and Zhang 1996).

Some linguists (e.g. L. Li 1990; Zhao and Zhang 1996) have made efforts to classify different types of separable verbs and demonstrated different linguistic facts about these types.  There are two major types of separable verbs:  V+N idioms with the verb-object relation and V+A/V idioms with the verb-modifier relation - when X is A or non-conjunctive V.[2]

The V+N idiom is a typical case which demonstrates the mismatch between a vocabulary word and grammar word.  There have been three different views on whether V+N idioms are words or phrases in Chinese grammar.

Given the fact that the V and the N can be separated in usage, the most popular view (e.g. Z. Lu 1957; L. Li 1990; Shi 1992) is that they are words when V+N are contiguous and they are phrases otherwise.  This analysis fails to account for the link between the separated use and the contiguous use of the idioms.  In terms of the type of V+N idioms like 洗澡 xi zao (wash-bath: take a bath), this analysis also fails to explain why a different structural analysis should be given to this type of contiguous V+N idioms listed in the lexicon than the analysis to the also contiguous but non-listable combination of V and N (e.g. 洗碗 xi wan 'wash dishes').[3]  As will be shown in Section 5.1, the structural distribution for this type of V+N idioms and the distribution for the corresponding non-listable combinations are identical.

Other grammarians argue that V+N idioms are not phrases (Lin 1983;  Q. Li 1983; Zhao and Zhang 1996).  They insist that they are words, or a special type of words.  This argument cannot explain the demonstrated variety of separated uses.

There are scholars (e.g. Lü 1989; Dai 1993) who indicate that idioms like 洗澡 xi zao are phrases.  Their judgment is based on their observation of the linguistic variations demonstrated by such idioms.  But they have not given detailed formal analyses which account for the difference between these V+N idioms and the non-listable V+NP constructions in the semantic compositionality.  That seems to be the major reason why this insightful argument has not convinced people with different views.

As for V+A/V idioms, Lü (1989) offers a theory that these idioms are words and the insertable signs between V and A/V are Chinese infixes.  This is an insightful hypothesis.  But as in the case of the analyses proposed for V+N idioms, no formal solutions have been proposed based on the analyses in the context of phrase structure grammars.  As a general goal, a good solution should not only be implementable, but also offer an analysis which captures the linguistic link, both structural and semantic, between the separated use and the contiguous use of separable verbs.  It is felt that there is still a distance between the proposed analyses reported in literature and achieving this goal of formally capturing the linguistic generality.

Three types of V+X idioms can be classified based on their different degrees of 'separability' between V and X, to be explored in three major sections of this chapter.  Section 5.1 studies the first type of V+N idioms like 洗澡 xi zao (wash-bath: take a bath).  These idioms are freely separable.  It is a relatively easy case.  Section 5.2 investigates the second type of the V+N idioms represented by 伤心 shang xin (hurt-heart: sad or heartbroken).  These idioms are less separable.  This category constitutes the largest part of the V+N phenomena.  It is a more difficult borderline case.  Section 5.3 studies the V+A/V idioms.  These idioms are least separable:  only the two modal signs 得 de3 (can) and 不 bu (cannot) can be inserted inside them, and nothing else.  For all these problems, arguments for the wordhood judgment will be presented first.  A corresponding morphological or syntactic analysis will be proposed, together with the formulation of the solution in CPSG95 based on the given analysis.

5.1. Verb-object Idioms: V+N I

The purpose of this section is to analyze the first type of V+N idioms, represented by 洗澡 xi zao (wash‑bath: take a bath).  The basic arguments to be presented are that they are verb phrases in Chinese syntax and the relationship between the V and the N is syntactic.  Based on these arguments, formal solutions to the problems involved in this construction will be presented.

The idioms like 洗澡 xi zao are classified as V+N I, to be distinguished from another type of idioms V+N II (see 5.2).  The following is a sample list of this type of idioms.

(5-1.) V+N I: xi zao type

洗澡 xi (wash) zao (bath #)              take a bath
擦澡 ca (scrub) zao (bath #)             clean one's body by scrubbing
吃亏 chi (eat) kui (loss #)                   get the worst
走路 zou (go) lu (way $)                      walk
吃饭 chi (eat) fan (rice $)                    have a meal
睡觉 shui (V:sleep) jiao (N:sleep #)   sleep
做梦 zuo (make) meng (N:dream)     dream (a dream)
吵架  chao (quarrel) jia (N:fight #)    quarrel (or have a row)
打仗 da (beat) zhang (battle)              fight a battle
上当 shang (get) dang (cheating #)                be taken in
拆台 chai (pull down) tai (platform #)          pull away a prop
见面 jian (see) mian (face #)                            meet (face to face)
磕头 ke (knock) tou (head)                              kowtow
带头 dai (lead) tou (head $)                            take the lead
帮忙 bang (help) mang (business #)              give a hand
告状 gao (sue) zhuang (complaint #)            lodge a complaint

Note: Many nouns (marked with # or $) in this type of constructions cannot be used independently of the corresponding V.[4]  But those with the mark $ have no such restriction in their literal sense.  For example, when the sign fan  means 'meal', as it does in the idiom, it cannot be used in a context other than the idiom chi-fan (have a meal).  Only when it stands for the literal meaning ‘rice’, it does not have to co-occur with  chi.

There is ample evidence for the phrasal status of the combinations like 洗澡 xi zao.  The evidence is of three types.  The first comes from the free insertion of some syntactic constituent X between the idioms in the form V+X+N: this involves keyword-based judgment patterns and other X‑insertion tests proposed in Chapter IV.  The second type of evidence resorts to some syntactic processes for the transitive VP, namely passivization and long-distance topicalization.  The V+N I idioms can be topicalized and passivized in the same way as ordinary transitive VP structures do.  The last piece of evidence comes from the reduplication process associated with this type of idiom.   All the evidence leads to the conclusion that V+N I idioms are syntactic in nature.

The first evidence comes from using the wordhood judgment pattern: V(X)+zhe/guo à word(X).  It is a well observed syntactic fact that Chinese aspectual markers appear right after a lexical verb (and before the direct object).  If 洗澡 xi zao were a lexical verb, the aspectual markers would appear after the combinations, not inside them.  But that is not the case, shown by the ungrammaticality of the example in (5-2b).  A productive transitive VP example is given in (5-3) to show its syntactic similarity (parallelness) with V+N I idioms.

(5-2.) (a)      他正在洗着澡
ta       zheng-zai    xi      zhe    zao.
he      right-now    wash ZHE   bath
He is taking a bath right now.

(b) *   他正在洗澡着。
ta       zheng-zai    xi-zao         zhe.
he      right-now    wash-bath   ZHE

(5-3.) (a)      他正在洗着衣服。
ta       zheng-zai    xi      zhe    yi-fu.
he      right-now    wash ZHE   clothes
He is washing the clothes right now.

(b) *   他正在洗衣服着。
ta       zheng-zai    xi      yi-fu           zhe.
he      right-now    wash clothes        ZHE

The above examples show that the aspectual marker 着 zhe (ZHE) should be inserted in the V+N idiom, just as it does in an ordinary transitive VP structure.

Further evidence for X-insertion is given below.   This comes from the post-verbal modifier of ‘action-times’ (动量补语 dongliang buyu) like 'once', 'twice', etc.  In Chinese, action-times modifiers appear after the lexical verb and aspectual marker (but before the object), as shown in (5-4a) and (5-5a).

(5-4.) (a)      他洗了两次澡。
ta       xi      le       liang  ci       zao.
he      wash LE     two    time   bath
He has taken a bath twice.

(b) *   他洗澡了两次。
ta       xi-zao         le       liang  ci.
he      wash-bath   LE     two    time

(5-5.) (a)      他洗了两次衣服。
ta       xi      le       liang  ci       yi-fu.
he      wash LE     two    time   clothes
He has washed the clothes twice.

(b) *   他洗衣服了两次。
ta       xi      yi-fu           le       liang  ci.
he      wash clothes        LE     two    time

So far, evidence has been provided of syntactic constituents which are attached to the verb in the V+N I idioms.  To further argue for the VP status of the whole idiom, it will be demonstrated that the N in the V+N I idioms in fact fills the syntactic NP position in the same way as all other objects do in Chinese transitive VP structures.  In fact, N in the V+N I does not have to be a bare N:  it can be legitimately expanded to a full-fledged NP (although it does not normally do so).  A full-fledged NP in Chinese typically consists of a classifier phrase (and modifiers like de-construction) before the noun.  Compare the following pair of examples.  Just like an ordinary NP 一件崭新的衣服 yi jian zan-xin de yi-fu (one piece of brand-new clothes), 一个痛快的澡 yi ge tong-kuai de zao (a comfortable bath) is a full-fledged NP.

(5-6.)           他洗了一个痛快的澡。
ta       xi      le       yi       ge      tong-kuai     de      zao.
he      wash LE     one    CLA   comfortable DE     bath
He has taken a comfortable bath.

(5-7.)           他洗了一件崭新的衣服。
ta       xi      le       yi       jian    zan-xin        de      yi-fu.
he      wash LE     one    CLA   brand-new  DE     clothes
He has washed one piece of brand-new clothes.

It requires attention that the above evidence is directly against the following widespread view, i.e. signs like 澡 zao, marked with # in (5-1), are 'bound morphemes' or ‘bound stems’ (e.g. L. Li 1990; Zhao and Zhang 1996).  As shown, like every other free morpheme noun (e.g. yi-fu), zao holds a lexical position in the typical Chinese NP sequence 'determiner + classifier + (de-construction) + N', e.g. 一个澡 yi ge zao (a bath), 一个痛快的澡 yi ge tong-kuai de zao (a comfortable bath).[5]  In fact, as long as the ‘V+N I phrase’ arguments are accepted (further evidence to come), by definition ‘bound morpheme’ is a misnomer for 澡 zao.  As a part of morphology, a bound morpheme cannot play a syntactic role:  it is inside a word and cannot be seen in syntax.  The analysis of 洗xi (...) 澡zao as a phrase entails the syntactic roles played by 澡 zao:  (i) 澡 zao is a free morpheme noun which fills the lexical position as the final N inside the possibly full-fledged NP;  (ii) 澡zao plays the object role in the syntactic transitive structure 洗澡xi zao.

This bound morpheme view is an argument used for demonstrating  the relevant V+N idioms to be words rather than phrases (e.g. L. Li 1990).  Further examination of this widely accepted view will help to strengthen the counter-arguments that all V+N I idioms are phrases.

Labeling signs like 澡zao (bath) as bound morphemes seem to come from an inappropriate interpretation of the statement that bound morphemes cannot be ‘freely’, or ‘independently’, used in syntax.[6]  This interpretation places an equal sign between the idiomatic co-occurrence constraint and ‘not being freely used’.  It is true that 澡zao is not an ordinary noun to be used in isolation.  There is a co-occurrence constraint in effect:  澡zao cannot be used without the appearance of 洗xi (or 擦ca).  However, the syntactic role played by 澡zao, the object in the syntactic VP structure, has full potential of being ‘freely’ used as any other Chinese NP object:   it can even be placed before the verb in long-distance constructions as shall be shown shortly.  A more proper interpretation of ‘not being freely used’ in terms of defining bound morphemes should be that a genuine bound morpheme, e.g. the suffix 性 -xing ‘-ness’, has to attach to another sign contiguously to form a word.

A comparison with similar phenomena in English may be helpful.  English also has similar idiomatic VPs, such as kick the bucket.[7]  For the same reason, it cannot be concluded that bucket (or the bucket) is a bound morpheme only because it demonstrates necessary co-occurrence with the verb literal kick.  Signs like bucket, 澡 zao (bath) are not of the same nature as bound morphemes like –less, -ly, un-, ‑xing (-ness), etc

The second type of evidence shows some pattern variations for the V+N I idioms.  These variations are typical syntactic patterns for the transitive V+NP structure in Chinese.  One of most frequently used patterns for transitive structures is the topical pattern of long distance dependency.  This provides strong evidence for judging the V+N I idioms as syntactic rather than morphological.  For, with the exception of clitics, morphological theories in general conceive of the parts of a word as being contiguous.[8]  Both the V+N I idiom and the normal V+NP structure can be topicalized, as shown in (5-8b) and (5-9b) below.

(5-8.) (a)      我认为他应该洗澡。
wo     ren-wei        ta       ying-gai       xi zao.
I         think           he      should        wash-bath
I think that he should take a bath.

(b)      澡我认为他应该洗
zao    wo     ren-wei        ta       ying-gai       xi.
bath  I         think           he      should        wash
The bath I think that he should take.

(5-9.) (a)       我认为他应该洗衣服。
wo     ren-wei        ta       ying-gai       xi      yi-fu.
I         think           he      should        wash clothes
I think that he should wash the clothes.

(b)      衣服我认为他应该洗。
yi-fu           wo     ren-wei        ta       ying-gai       xi.
clothes        I         think           he      should        wash
The clothes I think that he should wash.

The minimal pair of passive sentences in (5-10) and (5‑11) further demonstrates the syntactic nature of the V+N I structure.

(5-10.)         澡洗得很干净。
zao             xi      de3    hen    gan-jing.
bath            wash DE3   very   clean
A good bath was taken so that one was very clean.

(5-11.)         衣服洗得很干净。
yi-fu           xi      de3    hen    gan-jing.
clothes        wash DE3   very   clean
The clothes were washed clean.

The third type of evidence involves the nature of reduplication associated with such idioms.  For idioms like 洗澡 xi zao (take a bath), the first sign can be reduplicated to denote the shortness of the action:  洗澡 xi zao (take a bath) --> 洗洗澡 xi xi zao (take a short bath).  If 洗澡 xi zao is a word, by definition, 洗xi is a morpheme inside the word and 洗洗澡 xi-xi-zao belongs to morphological reduplication (AB-->AAB type).  However, this analysis fails to account for the generality of such reduplication:  it is a general rule in Chinese grammar that a verb reduplicates itself contiguously to denote the shortness of the action.  For example, 听音乐 ting (listen to) yin-yue (music) --> 听听音乐 ting ting yin-yue (listen to music for a while); 休息 xiu-xi (rest) --> 休息休息 xiu-xi xiu-xi (have a short rest), etc.  On the other hand, when we accept that 洗澡 xi zao is a verb-object phrase in syntax and the nature of this reduplication is accordingly judged as syntactic,[9] we come to a satisfactory and unified account for all the related data.  As a result, only one reduplication rule is required in CPSG95 to capture the general phenomena;[10]  there is no need to do anything special for V+N  idioms.

This AB ‑‑> AAB type reduplication problem for the V+N idioms poses a big challenge to traditional word segmenters (Sun and Huang 1996).  Moreover, even when a word segmenter successfully incorporates some procedure to cope with this problem, the essentially same rule has to be repeated in the grammar for the general VV reduplication.  This is not desirable in terms of capturing the linguistic generality.

All the evidence presented above indicates that idioms like 洗澡xi zao, no matter whether V and N are used contiguously or not, are not words, but phrases.  The idiomatic nature of such combinations seems to be the reason why most native speakers, including some linguists, regard them as words.  Lü (1989: 113-114) suggests that vocabulary words  like 洗澡 xi zao should be distinguished from grammar words.  He was one of the first Chinese grammarians who found that the V+N relation in the idioms like 洗澡 xi zao is a syntactic verb object relation.  But he did not provide full arguments for his view, neither did he offer a precise formalized analysis of this problem.[11]

As shown in the previous examples, the V+N I idioms do not differ from other transitive verb phrases in all major syntactic behaviors.   However, due to their idiomatic nature, the V+N I idioms are different from ordinary transitive VPs in the following two major aspects.  These differences need to be kept in mind when formulating the grammar to capture the phenomena.

• Semantics:  the semantics of the idiom should be given directly in the lexicon, not as a result of the computation of the semantics of the parts based on some general principle of compositionality.
• Co-occurrence requirement:  洗 xi (or 擦 ca) and 澡 zao must co-occur with each other;  走 zou (go) and 路 lu (way) must co-occur; etc.  This is a requirement specific to the idioms at issue.  For example, 洗 xi and 澡 zao must co-occur in order to stand as an idiom to mean ‘take a bath’.

Based on the study above, the CPSG95 solution to this problem is described below.  In order to enforce the co-occurrence of the V+N I idioms, it is specified in the CPSG95 lexicon that the head V obligatorily expects as its object an NP headed by a specific literal.  This treatment originates from the practice of handling collocations in HPSG.  In HPSG, there are features designed to enable the subcategorization for particular words, or phrases headed by particular words.  For example, the feature [NFORM there] and [NFORM it] refer to the expletive there and it respectively for the special treatment of existential constructions, cleft constructions, etc. (Pollard and Sag 1987:62).  The values of the feature PFORM distinguish individual prepositions like for, on, etc.  They are used in phrasal verbs like rely on NP, look for NP, etc.  In CPSG95, this approach is being generalized, as described below.

As presented before, the feature for orthography [HANZI] records the Chinese character string for each lexical sign.  When a specific lexical literal is required in an idiomatic expectation, the constraint is directly placed on the value of the feature [HANZI] of the expected sign, in addition to possible other constraints.  It is standard practice in a lexicalized grammar that the expected complement (object) for the transitive structure be coded directly in the entry of the head V in the lexicon.  Usually, the expected sign is just an ordinary NP.  In the idiomatic VP like 洗 xi (...) 澡 zao, one further constraint is placed:  the expected NP must be headed by the literal character 澡zao.  This treatment ensures that all pattern variations for transitive VP such as passive constructions, topicalized constructions, etc. in Chinese syntax will equally apply to the V+N I idioms.[12]

The difference in semantics is accommodated in the feature [CONTENT] of the head V with proper co-indexing.  In ordinary cases like 洗衣服 xi yi-fu (wash clothes), the argument structure is [vt_semantics] which requires two arguments, with the role [ARG2] filled by the semantics of the object NP.  In the idiomatic case 洗澡 xi zao (take a bath), the V and N form a semantic whole, coded as [RELN take_bath].[13]  The V+N I idioms are formulated like intransitive verbs in terms of composing the semantics - hence coded as [vi_semantics], with only one argument to be co-indexed with the subject NP.  Note that there are two lexical entries in the lexicon for the verb 洗 xi (wash), one for the ordinary use and the other for the idiom, shown in (5-12) and (5-13).

The above solution takes care of the syntactic similarity of the
V+N I idioms and ordinary V+NP structures.  It is also detailed enough to address their major differences.  In addition, the associated reduplication process (i.e. V+N --> V+V+N) is no longer a problem once this solution is adopted.  As the V in the V+N idioms is judged and coded as a lexical V (word) in this proposal, the reduplication rule which handles V --> VV will equally apply here.

5.2. Verb-object Idioms: V+N II

The purpose of this section is to provide an analysis of another type of V+N idiom and present the solution implemented in CPSG95 based on the analysis.

Examples like 洗澡 xi zao (take a bath) are in fact easy cases to judge.   There are more marginal cases.  When discussing Chinese verb-object idioms, L. Li (1990) and Shi (1992) indicate that the boundary between a word and a phrase in Chinese is far from clear-cut.  There is a remarkable “gray area” in between.  Examples in (5-14) are V+N II idioms, in contrast to the V+N I type, classified by L. Li (1990).

(5-14.) V+N II: 伤心 shang xin type

伤心 shang (hurt) xin (heart)             sad or break one's heart
担心 dan (carry) xin (heart)               worry
留神 liu (pay) shen (attention)           pay attention to
冒险 mao (take) xian (risk)                 take the risk
借光 jie (borrow) guang (light)           benefit from
劳驾 lao (bother) jia (vehicle)             beg the pardon
革命 ge (change) ming (life)                 make revolution
落后 luo (lag) hou (back)                      lag behind
放手 fang (release) shou (hand)          release one's hold

Compared with V+N I (洗澡xi zao type), V+N II has more characteristics of a word.  The lists below given by L. Li (1990) contrast their respective characteristics.[14]

(5-15.) V+N I (based on L. Li 1990:115-116)

(5-16.) V+N II (based on L. Li 1990:115)

For V+N I, the previous text has already given detailed analysis and evidence and decided that such idioms are phrases, not words.  This position is not affected by the demonstrated features (a1) and (a2) in (5‑15);  as argued before,  (a1) and (a2) do not contribute to the definition of a grammar word.

However, (a3), (a4) and (a5) are all syntactic evidence showing that V+N II idioms can be inserted in lexical positions.   On the other hand, these idioms also show the similarity with V+N I idioms in the features (b1), (b2) and (b3) as a phrase.  In particular, (a3) versus (b1) and (a4) versus (b2) demonstrate a 'minimal pair' of phrase features and word features.  The following is such a minimal pair example (with the same meaning as well) based on the feature pairs (a3) versus (b1), with a post-verbal modifier 透tou (thorough) and aspectual particle 了le (LE).  It demonstrates the borderline status of such idioms.  As before, a similar example of an ordinary transitive VP is also given below for comparison.

(5-17.)         V+N II: word or phrase?

伤心：sad; heart-broken
shang          xin
hurt            heart

(a)      我伤心透了
wo     shang-xin  tou              le.
I         sad              thorough     LE
I was extremely sad.

(b)      我伤透了心
wo     shang         tou              le       xin.
I         break          thorough     LE     heart
I was extremely sad.

(5-18.)         Ordinary V+NP phrase: 恨hen (hate) 他ta (he)

(a) *   我恨他透了
wo     hen   ta      tou              le.
I         hate   he      thorough     LE

(b)      我恨透了他
wo     hen   tou              le       ta.
I         hate   thorough     LE     he
I thoroughly hate him.

As shown in (5-18), in the common V+NP structure, the post-verbal modifier 透 tou (thorough) and the aspectual particle 了 le (perfect aspect) can only occur between the lexical V and NP.  But in many V+N II idioms, they may occur either after the V+N combination or in between.  In (5‑17a), 伤心 shang xin is in the lexical position because Chinese syntax requires that the post-verbal modifier attach to the lexical V, not to a VP as indicated in (5-18a).  Following the same argument, 伤 shang (hurt) alone in (5-17b) must be a lexical V as well.  The sign 心 xin (heart) in (5‑17b) establishes itself in syntax as object of the V, playing the same role as 他ta (he) in (5-18b).  These facts show clearly that V+N II idioms can be used both as lexical verbs and as transitive verb phrases.   In other words, before entering a context, while still in the lexicon, one can not rule out either possibility.

However, there is a clear cut condition for distinguishing its use as a word and its use as a phrase once a V+N II idiom is placed in a context.   It is observed that the only time a V+N II idiom assumes the lexical status is when V and N are contiguous.  In all other cases, i.e. when V and N are not contiguous, they behave essentially similar to the V+N I type.

In addition to the examples in (5-17) above, two more examples are given below to demonstrate the separated phrasal use of V+N II.  The first is the case V+X+N where X is a possessive modifier attached to the head N.  Note also the post-verbal position of 透 tou (thorough) and 了le (LE).  The second is an example of passivization when N occurs before V.  These examples provide strong evidence for the syntactic nature of V+N II idioms when V and N are not used contiguously.

(5-19.) (a) *   你伤他的心透了
ni       shang         ta       de      xin    tou              le.
you    hurt            she    DE     heart thorough     LE

(b)      你伤透了他的心
ni       shang         tou              le       ta       de      xin.
you    hurt            thorough     LE     she    DE     heart
You broke her heart.

(5-20.)         V+N II: instance of passive with or without 被 bei (BEI)

心（被）伤透了
xin    (bei)   shang         tou              le.
heart BEI    break          thorough     LE
The heart was completely broken.
or: (Someone) was extremely sad.

Based on the above investigation, it is proposed in CPSG95 that two distinct entries be constructed for each such idiom, one as an inseparable lexical V, and the other as a transitive VP just like that of V+N I.  Each entry covers its own part of the phenomena.  In order to capture the semantic link between the two entries, a lexical rule called V_N_II Rule is formulated in CPSG95, shown in (5-21).

The input to the V_N_II Lexical Rule is an entry with [CATEGORY v_n_ii] where [v_n_ii] is a given sub-category in the lexicon for V+N II type verbs.  The output is another entry with the same information except for three features [HANZI], [CATEGROY] and [COMP1_RIGHT].  The new value for [HANZI] is a list concatenating the old [HANZI] and the [HANZI] for the expected [COMP1_RIGHT].  The new [CATEGORY] value is simply [v].  The value for [COMP1_RIGHT] becomes [null].  The outline of the two entries captured by this lexical rule are shown in (5-22) and (5-23).

It needs to be pointed out that the definition of [CATEGORY v_n_ii] in CPSG95 is narrower than L. Li’s definition of V+N II type idioms.  As indicated by L. Li (1990), not all V+N II idioms share the same set of lexical features (a3), (a4) and (a5) as a word.  The definition in CPSG95 does not include the idioms which share the lexical feature (a5), i.e. taking a syntactic object.  These are idioms like 担心dan-xin (carry-heart: worry about).  For such idioms, when they are used as inseparable compound words, they can take a syntactic object.  This is not possible for all other V+N idioms, as shown below.

(5-24.) (a)     她很担心你
ta       hen    dan-xin                ni.
he      very   worry (about)        you
He is very concerned about you.

(b) *   他很伤心你
ta       hen    shang-xin            ni.
he      very   sad                       you

In addition, these idioms do not demonstrate the full distributional potential of transitive VP constructions.  The separated uses of these idioms are far more limited than other V+N idioms.  For example, they can hardly be passivized or topicalized as other V+N idioms can, as shown by the following minimal pair of passive constructions.

(5-25.)(a) *   心（被）担透了
xin    (bei)   dan             tou              le.
heart BEI    carry           thorough     LE

(b)      心（被）伤透了
xin    (bei)   shang         tou              le.
heart BEI    break          thorough     LE
The heart was completely broken.
or: (Someone) was extremely sad.

In fact, the separated use ('phrasal use') for such V+N idioms seems only limited to some type of X-insertion, typically the appearance of aspect signs between V and N.[15]  Such separated use is the only thing shared by all V+N idioms, as shown below.

(5-26.)(a)     他担过心
ta       dan             guo    xin
he      carry           GUO  heart
He (once) was worried.

(b)      他伤过心
ta       shang         guo    xin
he      break          GUO  heart
He (once) was heart-broken.

To summarize,  the V+N idioms like 担心 dan-xin which can take a syntactic object do not share sufficient generality with other V+N II idioms for a lexical rule to capture.  Therefore, such idioms are excluded from the [CATEGORY v_n_ii] type.  This makes these idioms not subject to the lexical rule proposed above.  It is left for future research to answer the question whether there is enough generality among this set of idioms to justify some general approach to this problem, say, another lexical rule or some other ways of generalization of the phenomena.  For time being, CPSG95 simply lists both the contiguous and separated uses of these idioms in the lexicon.[16]

It is worth noticing that leaving such idioms aside, this lexical rule still covers large parts of V+N II phenomena.  The idioms like 担心dan-xin only form a very small set which are in the state of transition to words per se (from the angle of language development) but which still retain some (but not complete) characteristics of a phrase.[17]

5.3. Verb-modifier Idioms: V+A/V

This section investigates the V+X idioms in the form of V+A/V.  The data for the interaction of V+A/V idioms and the modal insertion are presented first.  The subsequent text will argue for Lü's infix hypothesis for the modal insertion and accordingly propose a lexical rule to capture the idioms with or without modal insertion.

The following is a sample list of V+A/V idioms, represented by kan jian (look-see: have seen).

(5-27.) V+A/V: kan jian type

看见 kan (look) jian (see)                    have seen
看穿 kan (look) chuan (through)        see through
离开 li (leave) kai (off)                         leave
打倒 da (beat) dao (fall)                      down with
打败 da (beat) bai (fail)                       defeat
打赢 da (beat) ying (win)                    fight and win
睡着 shui (sleep) zhao (asleep)            fall asleep
进来 jin (enter) lai (come)                             enter
走开 zou (go) kai (off)                         go away
关上  guan (close) shang (up)             close

In the V+A/V idiom kan jian (have-seen), the first sign kan (look) is the head of the combination while the second jian (see) denotes the result.  So when we say, wo (I) kan-jian (see) ta (he), even without the aspectual marker le (LE) or guo (GUO), we know that it is a completed action:  'I have seen him' or 'I saw him'.[18]

Idioms like kan-jian (have-seen) function just as a lexical whole (transitive verb).  When there is an aspect marker, it is attached immediately after the idioms as shown in (5‑28).  This is strong evidence for judging V+A/V idioms as words, not as syntactic constructions.

(5-28.)         我看见了他
wo     kan jian     le       ta.
I         look-see       LE     he                   I have seen him.

The only observed separated use is that such idioms allow for two modal signs 得 de3 (can) and 不 bu (cannot) in between, shown by (5-29a) and (5-29b).  But no other signs, operations or processes can enter the internal structure of these idioms.

(5-29.) (a)     我看不见他
wo     kan bu jian         ta.
I         look cannot see     he
I cannot see him.

(c)      你看得见他吗？
ni       kan de3 jian       ta       me?
you    look can see          he      ME
Can you see him?

Note that English modal verbs ‘can’ and ‘cannot’ are used to translate these two modal signs.  In fact, Contemporary Mandarin also has corresponding modal verbs (能愿动词 neng-yuan dong-ci):  能 neng (can) and 不能 bu neng (cannot).  The major difference between Chinese modal verbs 能 neng / 不能 bu neng and the modal signs 得 de3 / 不 bu lies in their different distribution in syntax.  The use of modal signs 得 de3 (can) and 不 bu (cannot) is extremely restrictive:  they have to be inserted into V+BUYU combinations.  But Chinese modal verbs can be used before any VP structures.  It is interesting to see the cases when they are used together in one sentence, as shown in (5-30 a+b) below.  Note that the meaning difference between the two types of modal signs is subtle, as shown in the examples.

(5-30.)(a)     你看得见他吗？
ni       kan de3 jian         ta       me?
you    look can see          he      ME
Can you see him? (Is your eye-sight good enough?)

(b)      你能看见他吗？
ni       neng kan jian      ta       me?
you    can    see              he      ME
Can you see him?
(Note: This is used in more general sense. It covers (a) and more.)

(a+b)  你能看得见他吗？
ni       neng kan de3 jian         ta       me?
you    can    look can see          he      ME
Can you see him? (Is your eye-sight good enough?)

(5-31.)(a)     我看不见他
wo     kan bu jian           ta
I         look cannot see     he
I cannot see him. (My eye-sight is too poor.)

(b)      我不能看见他
wo     bu     neng kan jian      ta
I         not    can    see              he
I cannot see him. (Otherwise, I will go crazy.)

(a+b) 我不能看不见他
wo     bu     neng kan bu jian           ta.
I         not    can    look cannot see     he
I cannot stand not being able to see him.
(I have to keep him always within the reach of my sight.)

Lü (1989:127) indicates that the modal signs are in fact the only two infixes in Contemporary Chinese.  Following this infix hypothesis, there is a good account for all the data above.  In other words, the V+A/V idioms are V+BUYU compound words subject to the modal infixation.  The phenomena of 看得见 kan-de3-jian (can see) and 看不见 kan-bu-jian (cannot see) are therefore morphological by nature.  But Lü did not offer formal analysis for these idioms.

Thompson (1973) first proposed a lexical rule to derive the potential forms V+de3/bu+A/V from the V+A/V idioms.  The lexical rule approach seems to be most suitable for capturing the regularity of the V+A/V idioms and their infixation variants V+de3/bu+A/V.  The  approach taken in CPSG95 is similar to Thompson’s proposal.  More precisely, two lexical rules are formulated in CPSG95 to handle the infixation in V+A/V idioms.  This way, CPSG95 simply lists all V+A/V idioms in the lexicon as V+A/V type compound words, coded as [CATEGORY v_buyu].[19]  Such entries cover all the contiguous uses of the idioms.  It is up to the two lexical rules to produce two infixed entries to cover the separated uses of the idioms.

The change of the infixed entries from the original entry lies in the semantic contribution of the modal signs.  This is captured in the lexical rules in (5-32) and (5-33).  In case of V+de3+A/V, the Modal Infixation Lexical Rule I in (5-32) assigns the value [can] to the feature [MODAL] in the semantics.  As for V+bu+A/V, there is a setting  [POLARITY minus] used to represent the negation in the semantics, shown in (5-33).[20]

The following lexical entry shows the idiomatic compound 看见 kan-jian as coded in the CPSG95 lexicon (leaving some irrelevant details aside).   This entry satisfies the necessary condition for the proposed infixation lexical rules.

The modal infixation lexical rules will take this [v_buyu] type compound as input and produce two V+MODAL+BUYU entries.  As a result, new entries 看得见 kan-de3-jian (can see) and 看不见 kan-bu-jian (cannot see) as shown below are added to the lexicon.[21]

The above proposal offers a simple, effective way of capturing the linguistic data of the interaction of V+A/V idioms and the modal insertion, since it eliminates the need for any change of the general grammar in order to accommodate this type of separable verbs interacting with 得 de3 / 不 bu, the only two infixes in Chinese.

5.4. Summary

This chapter has conducted an inquiry into the linguistic phenomena of Chinese separable verbs, a long-standing difficult problem at the interface of Chinese compounding and syntax.   For each type of separable verb, arguments for the wordhood judgment have been presented.  Based on this judgment, CPSG95 provides analyses which capture both structural and semantic aspects of the constructions at issue.  The proposed solutions are formal and implementable.  All the solutions provide a way of capturing the link between the separated use and contiguous use of the V+X idioms.  The proposals presented in this chapter cover the vast majority of separable verbs.  Some unsolved rare cases or potential problems are also identified for further research.

----------------------------------------------------------------------

[1] They are also called phrasal verbs (duanyu dongci) or compound verbs (fuhe dongci) among Chinese grammarians.  For linguists who believe that they are compounds, the V+N separable verbs are often called verb object compounds and the V+A/V separable verbs resultative compounds.  The want of a uniform term for such phenomena reflects the borderline nature of these cases.  According to Zhao and Zhang (1996), out of the 3590 entries in the frequently used verb vocabulary, there are 355 separable V+N idioms.

[2] As the term 'separable verbs' gives people an impression that these verbs are words (which is not necessarily true), they are better called V+X (or V+N or V+A/V) idioms.

[3] There is no disagreement among Chinese grammarians for the verb-object combinations like xi wan:  they are analyzed as transitive verb phrases in all analyses, no matter whether the head V and the N is contiguous (e.g. xi wan 'wash dishes') or not (e.g. xi san ge wan 'wash three dishes').

[4] Such signs as zao (bath), which are marked with # in (5-1), are often labeled as 'bound morphemes' among Chinese grammarians, appearing only in idiomatic combinations like xi zao (take a bath), ca zao (clean one's body by scrubbing).  As will be shown shortly, bound morpheme is an inappropriate classification for these signs.

[5] It is widely acknowledged that the sequence num+classifier+noun is one typical form of Chinese NP in syntax.  The argument that zao is not a bound morpheme does not rely on any particular analysis of such Chinese NPs.  The fact that such a combination is generally regarded as syntactic ensures the validity of this argument.

[6] The notion ‘free’ or ‘freely’ is linked to the generally accepted view of regarding word as a minimal ‘free’ form, which can be traced back to classical linguistics works such as Bloomfield (1933).

[7] It is generally agreed that idioms like kick the bucket are not compounds but phrases (Zwicky 1989).

[8] That is the rationale behind the proposal of inseparability as important criterion for wordhood judgment in Lü (1989).

[9] In Chinese, reduplication is a general mechanism used both in morphology and syntax.  This thesis only addresses certain reduplication issues when they are linked to the morpho-syntactic problems under examination, but cannot elaborate on the Chinese reduplication phenomena in general.  The topic of Chinese reduplication deserves the study of a full-length dissertation.     

[10] In the ALE implementation of CPSG95, there is a VV Diminutive Reduplication Lexical Rule in place for phenomena like xi zao (take a bath) à xi xi zao (take a short bath);  ting yin-yue (listen to music) à ting ting yin-yue (listen to music for a while);  xiu-xi (rest) à xiu-xi xiu-xi (have a short rest).

[11] He observes that there are two distinct principles on wordhood.  The vocabulary principle requires that a word represent an integrated concept, not the simple composition of its parts.  Associated with the above is a tendency to regard as a word a relatively short string.  The grammatical principle, however, emphasizes the inseparability of the internal parts of a combination.  Based on the grammatical principle, xi zao is not a word, but a phrase.  This view is very insightful.

[12] The pattern variations are captured in CPSG95 by lexical rules following the HPSG tradition.  It is out of the scope of this thesis to present these rules in the CPSG95 syntax.  See W. Li (1996) for details.

[13] In the rare cases when the noun zao is realized in a full-fledged phrase like yi ge tong-kuai de zao (a comfortable bath), we may need some complicated special treatment in the building of the semantics.  Semantically, xi (wash) yi (one) ge (CLA) tong‑kuai (comfortable) de (DE) zao (bath): ‘take a comfortable bath’ actually means tong‑kuai (comfortable) de2 (DE2) xi (wash) yi (one) ci (time) zao (bath): ‘comfortably take a bath once’.  The syntactic modifier of the N zao is semantically a modifier attached to the whole idiom.  The classifier phrase of the N becomes the semantic 'action-times' modifier of the idiom.  The elaboration of semantics in such cases is left for future research.

[14] The two groups classified by L. Li (1990) are not restricted to the V+N combinations.  In order not to complicate the case,  only the comparison of the two groups of V+N idioms are discussed here.  Note also that in the tables, he used the term ‘bound morpheme’ (inappropriately) to refer to the co-occurrence constraint of the idioms.

[15] Another type of X-insertion is that N can occasionally be expanded by adding a de‑phrase modifier.  However, this use is really rare.

[16] Since they are only a small, easily listable set of verbs, and they only demonstrate limited separated uses (instead of full pattern variations of a transitive VP construction), to list these words and all their separated uses in the lexicon seems to be a better way than, say, trying to come up with another lexical rule just for this small set.  Listing such idiosyncratic use of language in the lexicon is common practice in NLP.

[17] In fact, this set has been becoming smaller because some idioms, say zhu-yi 'focus-attention: pay attention to', which used to be in this set, have already lost all separated phrasal uses and have become words per se.  Other idioms including dan-xin (worry about) are in the process of transition (called ionization by Chao 1968) with their increasing frequency of being used as words.   There is a fairly obvious tendency that they combine more and more closely as words, and become transparent to syntax.  It is expected that some, or all, of them will ultimately become words proper in future, just as zhu-yi did.

[18] In general, one cannot use kan-jian to translate English future tense 'will see', instead one should use the single-morpheme word kan:  I will see him --> wo (I) jiang (will) kan (see) ta (he).

[19] Of course, [v_buyu] is a sub-type of verb [v].

[20] The use of this feature for representing negation was suggested in  Footnote 18 in Pollard and Sag (1994:25)

[21] This is the procedural perspective of viewing the lexical rules.  As pointed out by Pollard and Sag (1987:209), “Lexical rules can be viewed from either a declarative or a procedural perspective: on the former view, they capture generalizations about static relationships between members of two or more word classes; on the latter view, they describe processes which produce the output from the input form.”

[Related]

PhD Thesis: Morpho-syntactic Interface in CPSG (cover page)

PhD Thesis: Chapter I Introduction

PhD Thesis: Chapter II Role of Grammar

PhD Thesis: Chapter III Design of CPSG95

PhD Thesis: Chapter IV Defining the Chinese Word

PhD Thesis: Chapter V Chinese Separable Verbs

PhD Thesis: Chapter VI Morpho-syntactic Interface Involving Derivation

PhD Thesis: Chapter VII Concluding Remarks

Overview of Natural Language Processing

Dr. Wei Li’s English Blog on NLP

4.0. Introduction

This chapter examines the linguistic definition of the Chinese word and establishes its formal representation in CPSG95.  This lays a foundation for the treatment of Chinese morpho-syntactic interface problems in later chapters.

To address issues on interfacing morphology and syntax in Chinese NLP, the fundamental question is:  what is a Chinese word?  A proper answer to this question defines the boundaries between morphology, the study of how morphemes combine into words, and syntax, the study of how words combine into phrases.  However, there is no easy answer to this question.

In fact, how to define Chinese words has been a central topic among Chinese grammarians for decades (Hu and Wen 1954; L. Wang 1955;  Z. Lu 1957; Lin 1983; Lü 1989; Shi 1992; Dai 1993; Zhao and Zhang 1996).  In late 50's, there was a heated discussion on the definition of Chinese word in China.  This discussion was induced by the campaign for the Chinese writing system reform (文字改革运动).  At that time, the government policy was to ultimately replace the Chinese characters (hanzi) by a Romanized writing system.  The system of pinyin, based on the Latin alphabet, was designed to represent the pronunciation of the characters in the Contemporary Mandarin.  The simplest way is to use pinyin as a writing system and simply translate Chinese characters into syllables in pinyin.  But it was soon found impractical due to the many-to-one correspondence from hanzi to syllable.  Text in pinyin with no  explicit word boundary delimiters is hardly comprehensible.   Linguists agree that the key issue for the feasibility of a pinyin-based writing system is to establish a standard or definition for Chinese words (Z. Lu 1957).  Once words can be identified by a common standard, the pinyin system can in principle be adopted for recording the Chinese language by using space and punctuation marks to separate words.  This is because the number of homophones at the word level is dramatically reduced when compared to the number of homophones at the hanzi (morpheme or monosyllabic) level.

But the definition of a Chinese word is a very complicated issue due to the existence of a considerable amount of borderline cases.  It has never been possible to reach a precise definition which can be applied to all circumstances and which can be accepted by linguists from different schools.

There have been many papers addressing the Chinese wordhood issue (e.g. Z. Lu 1957; Lin 1983; Lü 1989; Dai 1993).  Although there are still many problems in defining Chinese words for borderline cases and more debate will continue for many years to come, the understanding of Chinese wordhood has been deepened in the general acknowledgement of the following key aspects:  (i) the distinct status of Chinese morphology;  (ii) the distinction of different notions of word;  and (iii) the lack of absolute definition across systems or theories.

Almost all Chinese grammarians agree that unlike Classical Chinese, Contemporary Chinese is not based on single-morpheme words.   In other words, the word and the morpheme are no longer coextensive in Contemporary Chinese.[1]  In fact, that is the reason why we need to define Chinese morphology.  If the word and the morpheme stand for the same linguistic object in a language, like Classical Chinese, the definition of  morpheme will entail the definition of word and there is no role of morphology.

As it stands, there is little debate on the definition of morpheme in Chinese.  It is generally acknowledged that each syllable (or its corresponding written form hanzi) corresponds to (at least) one morpheme.  In a characteristic ‘isolating language’ - Classical Chinese is close to this, there is no or very poor morphology.[2]  However, Contemporary Chinese contains a significant number of bound morphemes in word formation (Dai 1993).  In particular, it is observed that many affixes are highly productive (Lü et al 1980).

It is widely acknowledged that the grammar of Contemporary Chinese is not complete without the component of morphology (Z. Lu 1957; Chao 1968; Li and Thompson 1981; Dai 1993; etc.).   Based on this widely accepted assumption, one major task for this thesis is to argue for the proper place to cut the line between morphology and syntax, and to explore effective ways of interleaving the two for analysis.

A significant development concerning the Chinese wordhood study is the  distinction between two different notions of word:  grammar word versus vocabulary word.  It is now clear that in terms of grammar analysis, a vocabulary word is not an appropriate notion (Lü 1989; more discussion to come in 4.1).

Decades of debate and discussion on the definition of a Chinese word have also shown that an operational definition for a grammar word precise enough to apply to all cases can hardly be established across systems or theories.  But a computational grammar of Chinese cannot be developed without precise definitions.  This leads to an argument in favor of the system internal wordhood definition and the interface coordination within a grammar.

The remaining sections of this chapter are organized like this.  Section 4.1 examines two notions of word.  Making sure that we use the right notion based on some appropriate guideline, some operational methods for judging a Chinese grammar word will be developed in 4.2.  Section 4.3 demonstrates the formal representation of a word in CPSG95.  This formalization is based on the design of expectation feature structures and the structural feature structure  presented in Chapter III.

4.1. Two Notions of Word

This section examines the two notions of word which have caused confusion.  The first notion, namely vocabulary word, is easy to define.  However, for the second notion, namely, grammar word, unfortunately,  no operational definition has been available.  It will be argued that a feasible alternative is to system internally define a grammar word and the labor division between Chinese morphology and syntax.

A grammar word stands for the grammatical unit which fits in the hierarchy of morpheme, word and phrase in linguistic analysis.  This gives the general concept of this notion but it is by no means an operational definition.  Vocabulary word, on the other hand, refers to the listed entry in the lexicon.  This definition is simple and unambiguous once a lexicon is given.  The lexical lookup will generate vocabulary words as potential building blocks for analysis.

On one hand, vocabulary words come from the lexicon;  they are basic building blocks for linguistic analysis.  On the other hand, as the ‘resulting’ unit for morphological analysis as well as the ‘starting’ or ‘atomic’ unit for syntactic analysis, the grammar word is the notion for linguistic generalization.  But it is observed that a vocabulary word is not necessarily a grammar word and vice versa.  It is this possible mismatch between vocabulary word and grammar word that has caused a problem in both Chinese grammar research and Chinese NLP system development.

Lü (1989) indicates that not making a distinction between these two notions of word has caused considerable confusion on the definition of Chinese word in the literature.  He further points out that only the former notion should be used in the grammar research.

Di Sciullo and Williams (1987) have similar ideas on these two notions of word.  They indicate that a sign listable in the lexicon corresponds to no certain grammatical unit.[3]   It can be a morpheme, a (grammar) word, or a phrase including sentence.  Some examples of different kinds of Chinese vocabulary words are given below to demonstrate this insight.

(4-1.) sample Chinese vocabulary words

(a) 性           bound morpheme, noun suffix, ‘-ness’
(b) 洗           free morpheme or word, V: ‘wash’
(c) 澡           word (only used in idioms), N: ‘bath’
(d) 澡盆        compound word, N: ‘bath-tub’
(e) 洗澡        idiom phrase, VP: ‘take a bath’
(f) 他们         pronoun as noun phrase, NP: ‘they’
(g) 城门失火，殃及池鱼

idiomatic sentence, S:
‘When the gate of a city is on fire, the fish in the
canal around the gate is also endangered.’

The above signs are all Chinese vocabulary words.  But grammatically, they do not necessarily function as a grammar word.  For example, (4-1a) functions as a suffix, smaller than a word.  (4-1e) behaves like a transitive VP (see 5.1 for more evidence), and (4-1g) acts as a sentence, both larger than a word.  The consequence of mixing up these different units in a grammar is the loss of power for a grammar to capture the linguistic generality for each level of grammatical unit.

The definition of grammar word has been a contentious issue in general linguistics (Di Sciullo and Williams 1987).  Its precise definition is particularly difficult in Chinese linguistics as there is a considerable amount of phenomena marginal between Chinese morphology and syntax (Zhu 1985; L. Li 1990; Sun and Huang 1996).  The morpheme-word-phrase transition is a continuous band in the linguistic reality.  Different grammars may well cut the division differently.  As long as there is no contradiction in coordinating these objects within the grammar, there does not seem to exist absolute judgment on which definition is right and which is wrong.

It is generally agreed that a grammar word is the smallest unit in syntax (Lü 1989), as also emphasized by Di Sciullo and Williams (1987) on the 'syntactic atomicity' of word.[4]  But this statement only serves as a guideline in theory, it is not an operational definition for the following reason.  It is logically circular to define word, smallest unit in syntax, and syntax, study of how words combine into phrases, one upon the other.

To avoid this 'circular definition' problem, a feasible alternative is to system internally define grammar word and the labor division between Chinese morphology and syntax, as in the case of CPSG95.  Of course, the system internal definition still needs to be justified based on the proposed morphological or syntactic analysis of borderline phenomena in terms of capturing the linguistic generality.  More specifically, three things need to be done:  (i) argue for the analysis case by case, e.g. why a certain construction should be treated as a morphological or syntactic phenomenon, what linguistic generality is captured by such a treatment, etc.;  (ii) establish some operational methods for wordhood judgment to cover similar cases;  (iii) use formalized data structures to represent the linguistic units after the wordhood judgment is made.  Section 4.2 will handle task (ii) and Section 4.3 is devoted to the formal definition of word required by task (iii).   The task in (i) will be pursued in the remaining chapters.

Another important notion related to grammar word is unlisted word.  Conceptually, an unlisted word is a novel construction formed via morphological rules, e.g. a derived word like 可读性 ke-du-xing (-able-read-ness: readability), foolish-ness, a compound person name (given name + family name) such as John Smith, 毛泽东 mao-ze-dong (Mao Zedong).  Unlisted words are often rule-based.  This is where productive word formation sets in.

However, unlisted word is not a crystal clear notion, just like the underlying concept grammar word.  Many grammarians have observed that phrases and unlisted words in Chinese are formed under similar rules (e.g. Zhu 1985; J. Lu 1988).  As both syntactic constructions and unlisted words are rule based, it can be difficult to judge a significant amount of borderline constructions as morphological or syntactic.

There are fuzzy cases where a construction is regarded as a grammar word by one and judged as a syntactic construction by another.  For example, while san (three) ge (CLA) is regarded as a syntactic construction, namely numeral-classifier phrase, in many grammars including CPSG95, such constructions are treated as compound words by others (e.g. Chen and Liu 1992).  ‘Quasi-affixation’ presents another outstanding ‘gray area’ (see 6.2).

The difficulty in handling the borderline phenomena leads back to the argument that the labor division between Chinese morphology and syntax should be pursued system internally and argued case by case in terms of capturing the linguistic generality.  To implement the required system internal definition, it is desirable to investigate practical wordhood judgment methods in addition to case-by-case arguments.  Some judgment methods will be developed in 4.2.  Case-by-case arguments and analysis for specific phenomena will be presented in later chapters.  After the wordhood judgment is made, there is a need for the formal representation.  Section 4.3 defines the formal representation of word with illustrations.

4.2. Judgment Methods

This section proposes some operational wordhood judgment methods based on the notion of ‘syntactic atomicity’ (Di Sciullo and Williams 1987).  These methods should be applied in combination with arguments of the associated grammatical analysis.  In fact, whether a sign is judged as a morpheme, a grammar word or a phrase ultimately depends on the related grammatical analysis.  However, the operationality of these methods will help facilitate the later analysis for some individual problems and avoid unnecessary repetition of similar arguments.

Most methods proposed for Chinese wordhood judgment in the literature are not fully operational.  For example, Chao (1968) agrees with Z. Lu (1957) that a word can fill the functional frame of a typical syntactic structure.  Dai (1993) points out that this method may effectively separate bound morphemes from free words, it cannot differentiate between words and phrases, as phrases may also be positioned in a syntactic frame.  In fact, whether this method can indeed separate bound morphemes from free words is still a problem.  This method cannot be made operational unless the definition of ‘frame of a typical syntactic structure’ is given.  The judgment methods proposed in this section try to avoid this ‘lack of operationality’ problem.

Dai (1993) made a serious effort in proposing a series of methods for cutting the line between morphemes and syntactic units in Chinese.  These methods have significantly advanced the study of this topic.  However, Dai admits that there is limitation associated with these proposals.  While each proposed method provides a sufficient (but not necessary) condition for judging whether a unit is a morpheme,  none of the methods can further determine whether this unit is a word or a phrase.  For example, the method of syntactic independence tests whether a unit in a question can be used as a short answer to the question.  If yes, the syntactic independence is confirmed and this unit is not a morpheme inside a word.  Obviously, such a method tells nothing about the syntactic rank of the tested unit because a word, a phrase or clause can all serve as an answer to a question.  In order to achieve that, other methods and/or analyses need to be brought in.

The first judgment method proposed below involves passivization and topicalization tests.  In essence, this is to see whether a string involves syntactic processes.  As an atomic unit, the internal structure of a word is transparent to syntax.  It follows that no syntactic processes are allowed to exert effects on the internal structure of a word.[5]  As  passivization and topicalization are generally acknowledged to be typical syntactic processes, if a potential combination A+B is subject to passivization B+bei+A and topicalization B+…+NP+A, it can be concluded that A+B is not a word:   the relation between A and B must be syntactic.

The second method is to define an unambiguous pattern for the wordhood judgment, namely, judgment patterns.  Judgment patterns are by no means a new concept.  In particular, keyword based judgment patterns have been frequently used in the literature of Chinese linguistics as a handy way for deterministic word category detection (e.g. L. Wang 1955;  Zhu 1985; Lü 1989).

The following keyword (i.e. aspect markers) based patterns are proposed for  judging a verb sign.

(4-2.)
(a) V(X)+着/过 --> word(X)
(b) V(X)+着/过/了+NP --> word(X)

The pattern (4-2a) states that if X is a sign of verb, no matter transitive or intransitive, appearing immediately before zhe/guo, then X is a word.  This proposal is backed by the following argument.  It is an important and widely acknowledged grammatical generalization in Chinese syntax that the aspect markers appear immediately after lexical verbs (Lü et al 1980).

Note that the aspect marker le (LE) is excluded from the pattern in (4-2a) because the same keyword le corresponds to two distinctive morphemes in Chinese:  the aspect le (LE) attaches to a lexical V while the sentence-final le (LEs) attaches to a VP (Lü et al 1980).  Therefore, judgment cannot be reliably made when a sentence ends in X+le, for example, when X is an intransitive verb or a transitive verb with the optional object omitted.  However, le in pattern (4-2b) has no problem since le is not in the ambiguous sentence final position.  This pattern says that if any of the three aspect markers appears between a sign X of verb and NP, X must be a word:  in fact, it is a lexical transitive verb.

There are two ways to use the judgment patterns.  If a sub-string of the input sentence matches a judgment pattern, one reaches the conclusion promptly.  If the input string does not match a pattern directly, one can still make indirect use of the patterns for judgment.  The idiomatic combination xi (wash) zao (bath) is a representative example.   Assume that the vocabulary word xi zao is a grammar word.  It follows that it should be able to fill in the lexical verb position in the judgment pattern (4-2a).  We then make a sentence which contains a substring matching the pattern to see whether it is grammatical.  The result is ungrammatical:  * 他洗澡着 ta (he) xi-zao (V) zhe (ZHE);  * 他洗澡过 ta (he) xi-zao (V) guo (GUO).  Therefore, our assumption must be wrong:  洗澡 xi zao is not a grammar word.  We then change the assumption and try to insert aspect markers inside them (it is in fact an expansion test, to be discussed shortly).  The new assumption is that the verb xi alone is a grammar word.  What we get are perfectly grammatical sentences and they match the pattern (4-2b):  他洗着澡 ta (he) xi (V) zhe (ZHE) zao (bath): ‘He is taking a bath’;  他洗过澡 ta (he) xi (V) guo (GUO) zao (bath): ‘He has taken the bath’.  Therefore the assumption is proven to be correct.  This way, all V+X combinations can be judged based on the judgment patterns (4-2a) or (4-2b).

The third method proposed below involves a more general expansion test.  As an atomic unit in syntax, the internal parts of a word are in principle not separable.[6]  Lü (1989) emphasized inseparability as a criterion for judging grammar words.  But he did not give instructions how this criterion should be applied.  Nevertheless, many linguists (e.g. Bloomfield 1933; Z. Lu 1957;  Lyons 1968; Dai 1993) have discussed expansion tests one way or another in assisting the wordhood judgment.

The method of expansion to be presented below for wordhood judgment is called X-insertion.  X-insertion is based on Di Sciullo and Williams’ thesis of the syntactic atomicity of word.  The rationale is that the internal parts of a word cannot be separated by syntactic constituents.

As a method, how to perform X-insertion is defined as follows.   Suppose that one needs to judge whether the combination A+B is a word.   If a sign X can be found to satisfy the following condition, then A+B is not a word, but a syntactic combination:  (i) A+X+B is a grammatical string,  (ii) X is not a bound morpheme, and (iii) the sub-structure [A+X] is headed by A or the sub-string [X+B] is headed by B.

The first constraint is self-evident:  a syntactic combination is necessarily a grammatical string.  The second constraint aims at  eliminating the danger of wrongly applying an infix here.  In fact, if X is a morphological infix, the conclusion would be just opposite:  A+B is a word.  The last constraint states that X must be a dependant of the head A (or B).  Otherwise, it results in a different structure.  There is no direct structural relation between A and B when A (or B) is a dependant of the head X in the structure.  Therefore, the question of whether A+B is a phrase or a word does not apply in the first place.

After the wordhood judgment is made on strings of signs based on the above judgment methods and/or the arguments for the analysis involved, the next step is to have them properly represented (coded) in the grammar formalism used.  This is the topic to be presented in 4.3 below.

4.3. Formal Representation of Word

The expectation feature structure and structural phrase structure in the mono-stratal design of CPSG95 presented in Chapter III provide means for the formal definition of the basic unit word in CPSG95.  Once the wordhood judgment for a unit is made based on arguments for a structural analysis and/or using the methods presented in Section 4.2., the formal representation is required for coding it in CPSG95.

This type of formalization is required to ensure its implementability in enforcing a required configurational constraint.  For example, the suffix 性 -xing expects an adjective word to form an abstract noun, such constraints [CATEGORY a] and @word can be placed in the morphological expectation feature [SUFFIXING].  These constraints will permit, for example, the legitimately derived word 严肃性 [yan-su]-xing] (serious-ness), but will block the following combination * 非常严肃性 [[fei-chang yan-su]-xing] (very-serious-ness).  This is because 非常严肃 [fei-chang yan-su] violates the formal constraint as given in the word definition:  it is not an atomic unit in syntax.

In CPSG95, word is defined as a syntactically atomic unit without obligatory morphological expectations, formally represented in the following macro.

word macro
a_sign
PREFIXING saturated | optional
SUFFIXING saturated | optional
STRUCT no_syn_dtr

Note that the above formal definition uses the sorted hierarchy [struct] for the structural feature structure and the sorted hierarchy [expected] for the expectation feature structure.  The definitions of these feature structures have been given in the preceding Chapter III.

Based on the sorted hierarchy struct: {syn_dtr, no_syn_dtr}, the constraint [no_syn_dtr] ensures that the word sign do not contain any syntactic daughter.[7]  This prevents syntactic constructions from being treated as words.  On the other hand, since [saturated], [obligatory] and [optional] are three subtypes of [expected], the constraint [saturated|optional] prevents a bound morpheme, say a prefix or suffix which has obligatory expectation in [PREFIXING] or [SUFFIXING], from being treated as a word.

This macro definition covers the representation of mono-morpheme words, e.g. 鹅 e ‘goose’, 读 du ‘read’, etc., or multi-morpheme words, e.g. 小看 xiao-kan ‘look down upon’, 天鹅 tian-e ‘swan’, etc., as well as unlisted words such as derived words whose internal morphological structures have already been formed.  Some typical examples of word are shown below.

For a derived word, note that the specification of [PREFIXING satisfied] and [STRUCT prefix], or [SUFFIXING satisfied] and [STRUCT suffix], assigned by the corresponding PS rule is compatible with the macro word definition.

The above word definition is an extension of the corresponding representation features from HPSG (Pollard and Sag 1987).  HPSG uses a binary structural feature [LEX] to distinguish lexical signs, [LEX +], and non-lexical signs, [LEX -].  In addition, [sign] is divided into [lexical_sign] and [phrasal_sign].[8]  Except for the one-to-one correspondence between [phrasal_sign] and [syn_dtr] in terms of rank (which stands for non-atomic syntactic constructs including phrases), neither of these HPSG binary divisions account for the distinction between a bound morpheme and a free morpheme.  Such a distinction is not necessary in HPSG because bound morphemes are assumed to be processed in the preprocessing stage (e.g. lexical rules for English inflection, Pollard and Sag 1987) and do not show themselves as independent input to the parser.  As CPSG95 involves both derivation morphology and syntax in an integrated general grammar, the HPSG binary divisions are no longer sufficient for formalizing the word definition.  ‘Word’ in CPSG95 needs to be distinguished with proper constraints from not only syntactic constructs, but also from affixes (bound morphemes).

In CPSG95, as productive derivation is designed to be an integrated component of the grammar, the word definition is both specified in the lexicon for some free morpheme words and assigned by the rules in morphological analysis.  This practice in essence follows one  suggestion in the original HPSG book:  "we might divide rules of grammar into two classes: rules of word formation, including compounding rules, which introduce the specification [LEX +] on the mother, and other rules, which introduce [LEX -] on the mother." (Pollard and Sag 1987:73).

It is worth noticing that words thus defined can fill either a morphological position or a syntactic position.  This reflects the interface nature of word:  word is an eligible unit in both morphology and syntax.  This is in contrast to bound morphemes which can only be internal parts of morphology.

In morphology, derivation combines a word and an affix into a derived word.  These derivatives are eligible to feed morphology again.   This is shown above by the examples in (4-5) and (4-6).  The adjective word 可读 ke-du (read-able) is derived from the prefix morpheme 可 ke- (-able) and the word 读 du (read).  Like other adjective words, this derived word can further combine with the suffix 性
–xing (-ness) in morphology.  It can also directly enter syntax, as all words do.

To syntax, all words are atomic units.  If a lexical position is specified, via the macro constraint @word in CPSG95, in a syntactic pattern, it makes no difference whether a filler of this position is a listed grammar word, or an unlisted word such as a derivative.  Such distinction is transparent to the syntactic structure.

4.4. Summary

Efforts have been made to reach a better understanding of Chinese wordhood in theory, methodology and formalization.  The main spirit of the HPSG theory and Di Sciullo and Williams' ‘syntactic atomicity’ theory has been applied to the study of Chinese wordhood and its formal representation.  Some effective wordhood judgment methods have also been proposed, based on theoretical guidelines.

The above work in the area of Chinese wordhood study provides a sound foundation for the analysis of the specific Chinese morpho-syntactic interface problems in Chapter V and Chapter VI.

-------------------------------------------------------

[1] For Classical Chinese, word, morpheme, syllable and hanzi are presumably all co-extensive.  This is the so-called Monosyllabic Myth of Chinese (DeFrancis 1984: ch.8).  The development of large numbers of homophones, mainly due to the loss of coda stops, has led to the development of large quantities of bi-syllabic and poly-syllabic word-like expressions (Chen and Wang 1975).

[2] Classical Chinese arguably allows for a certain degree of compounding.  In the linguistic literature, some linguists (e.g. Sapir 1921; Zhang 1957; Jensen 1990) did not strictly distinguish Contemporay/Modern Chinese from Classical Chinese and they held the general view that Chinese has little morphology except for limited compounding.  But this view of Contemporary Chinese has been criticized as misconception (Dai 1993) and is no longer accepted by the community of Chinese grammarians.

[3] Di Sciullo and Williams call a sign listable in the lexicon listeme, equivalent to the notion vocabulary word.

[4] In the literature, variations of  this view include the Lexicalist position (Chomsky 1970), the Lexical Integrity Hypothesis (Jackendoff 1972), the Principle of Morphology-Free Syntax (Zwicky 1987), etc.

[5] This type of ‘atomicity’ constraint (Di Sciullo and Williams 1987) is generally known as Lexical Integrity Hypothesis (LIH, Jackendoff 1972), which states that syntactic rules or operations cannot refer to part of a word.  A more elaborate version of LIH is proposed by Zwicky (1987) as a Principle of Morphology-Free Syntax.  This principle states that syntactic rules cannot make reference to the internal morphological composition of words.  The only lexical properties accessible to syntax, according to Zwicky, are syntactic category, subcategory, and features like gender, case, person, etc.

[6] Of course, in theory a word may be separated by morphological infix.  But except for the two modal signs de3 (can) and bu (cannot) (see Section 5.3 in Chapter V), there does not seem to exist infixation in Mandarin Chinese.

[7] In terms of rank, [no_syn_dtr] in CPSG95 corresponds to the type [lexical_sign] in HPSG (Pollard and Sag 1987).  A binary division between [lexical_sign] and [phrasal_sign] is enough in HPSG to distinguish the atomic unit word from syntactic construction.  But, as CPSG95 incorporates derivation in the general grammar, [no_syn_dtr] covers for both free morphemes and bound morphemes.  That is why the [no_syn_dtr] constraint on [STRUCT] alone cannot define word in CPSG95;  it needs to involve constraints on morphological expectation structures as well, as shown in the macro definition.

[8] Note that there are [LEX -] signs which are not of the type [phrasal_sign].

[Related]

PhD Thesis: Morpho-syntactic Interface in CPSG (cover page)

PhD Thesis: Chapter I Introduction

PhD Thesis: Chapter II Role of Grammar

PhD Thesis: Chapter III Design of CPSG95

PhD Thesis: Chapter IV Defining the Chinese Word

PhD Thesis: Chapter V Chinese Separable Verbs

PhD Thesis: Chapter VI Morpho-syntactic Interface Involving Derivation

PhD Thesis: Chapter VII Concluding Remarks

Overview of Natural Language Processing

Dr. Wei Li’s English Blog on NLP

3.0. Introduction

CPSG95 is the grammar designed to formalize the morpho-syntactic analysis presented in this dissertation.  This chapter presents the general design of CPSG95 with emphasis on three essential aspects related to the morpho-syntactic interface:  (i) the overall mono-stratal design of the sign;  (ii) the design of expectation feature structures;  (iii) the design of structural feature structures.

The HPSG-style mono-stratal design of the sign in CPSG95 provides a general framework for the information flow between different components of a grammar via unification.  Morphology, syntax and semantics are all accommodated in distinct features of a sign.  An example will be shown to illustrate the information flow between these components.

Expectation feature structures are designed to accommodate lexical information for the structural combination.  Expectation feature structures are vital to a lexicalized grammar like CPSG95.  The formal definition for the sort hierarchy [expected] for the expectation features will be given.  It will be demonstrated that the defined sort hierarchy provides means for imposing a proper structural hierarchy as defined by the general grammar.

One characteristic of the CPSG95 structural expectation is the unique design of morphological expectation features to incorporate Chinese productive derivation.  This design is believed to be a feasible and natural way of modeling Chinese derivation, as shall be presented shortly below and elaborated in section 3.2.1.  How this design benefits the interface coordination between derivation and syntax will be further demonstrated in Chapter VI.

The type [expected] for the expectation features is similar to the HPSG definition of [subcat] and [mod].  They both accommodate lexical expectation information to drive the analysis conducted via the general grammar.  In order to meet some requirements induced by introducing morphology into the general grammar and by accommodating linguistic characteristics of Chinese, three major modifications from the standard HPSG are proposed in CPSG95.  They are:  (i) the CPSG95 type [expected] is more generalized as to cover productive derivation in addition to syntactic subcategorization and modification;  (ii) unlike HPSG which tries to capture word order phenomena as independent constraints, Chinese word order in CPSG95 is integrated in the definition of the expectation features and the corresponding morphological/syntactic relations;  (iii) in terms of handling the syntactic subcategorization, CPSG95 pursues a non-list alternative to the standard practice of HPSG relying on the list design of obliqueness hierarchy.  The rationale and arguments for these modifications are presented in the corresponding sections, with a brief summary given below.

The first modification is necessitated by meeting the needs of introducing Chinese productive derivation into the grammar.  It is observed that a Chinese affix acts as the head daughter of the derivative in terms of expectation (Dai 1993).  The expectation information that drives the analysis of a Chinese productive derivation is found to be capturable lexically by the affix sign;  this is very similar to how the information for the head-driven syntactic analysis is captured in HPSG.  The expansion of the expectation notion to include productive morphology can account for a wider range of linguistic phenomena.  The feasibility of this modification has been verified by the implementation of CPSG95 based on the generalized expectation feature structures.

One outstanding characteristic of all the expectation features designed in CPSG95 is that the word order information is implied in the definition of these features.[1]  Word order constraints in CPSG95 are captured by individual PS rules for the structural relationship between the constituents.  In other words, Chinese word order constraints are not treated as phenomena which have sufficient generalizations of themselves independent of the individual morphological or syntactic relations.  This is very different from the word order treatment in theories like HPSG (Pollard and Sag 1987) and GPSG (Gazdar, Klein, Pullum and Sag 1985).  However, a similar treatment can be found in the work from  the school of ‘categorial grammar’ (e.g. Dowty 1982).

The word order theory in HPSG and GPSG is based on the assumption that structural relations and syntactic roles can be defined without involving the factor of word order.  In other words, it is assumed that the structural nature of a constituent (subject, object, etc.) and its linear position in the related structures can be studied separately.  This assumption is found to be inappropriate in capturing Chinese structural relations.  So far, no one has been able to propose an operational definition for Chinese structural relations and morphological/syntactic roles without bringing in word order.[2]

As Ding (1953) points out, without the means of inflections and case markers, word order is a primary constraint for defining and distinguishing Chinese structural relations.[3]  In terms of expectation, it can always be lexically decided where for the head sign to look for its expected daughter(s).  It is thus natural to design the expectation features directly on their expected word order.

The reason for the non-list design in capturing Chinese subcategorization can be summarized as follows:  (i) there has been no successful attempt by anyone, including the initial effort involved in the CPSG95 experiment, which demonstrates that the obliqueness design can be applied to Chinese grammar with sufficient linguistic generalizations;  (ii) it is found that the atomic approach with separate features for each complement is a feasible and flexible proposal in representing the relevant linguistic phenomena.

Finally, the design of the structural feature [STRUCT]  originates from [LEX + | -] in HPSG (Pollard and Sag 1987).  Unlike the binary type for [LEX], the type [struct] for [STRUCT] forms an elaborate sort hierarchy.  This is designed to meet the configurational requirements of introducing morphology into CPSG95.  This feature structure, together with the design of expectation feature structures, will help create a favorable framework for handling Chinese morpho-syntactic interface.  The proposed structural feature structure and the expectation feature structures contribute to the formal definition of linguistic units in CPSG95.  Such definitions enable proper lexical configurational constraints to be imposed on the expected signs when required.

3.1. Mono-stratal Design of Sign

This section presents the data structure involving the interface between morphology, syntax and semantics in CPSG95.  This is done by defining the mono-stratal design of the fundamental notion sign and by illustrating how different components, represented by the distinct features for the sign, interact.

As a dynamic unit of grammatical analysis, a sign can be a morpheme, a word, a phrase or a sentence.  It is the most fundamental object of HPSG-style grammars.  Formally, a sign is defined in CPSG95 by the type [a_sign], as shown below.[4]

(3-1.) Definition: a_sign

a_sign
HANZI                            hanzi_list
CONTENT                      content
CATEGORY                    category
SUBJ                               expected
COMP0_LEFT               expected
COMP1_RIGHT             expected
COMP2_RIGHT             expected
MOD_LEFT                    expected
MOD_RIGHT                  expected
PREFIXING                    expected
SUFFIXING                    expected
STRUCT                          struct

The type [a_sign] introduces a set of linguistic features for the description of a sign.  These are features for orthography, morphology, syntax and semantics, etc.[5]  The types, which are eligible to be the values of these features, have their own definitions in the sort hierarchy.  An introduction of these features follows.

The orthographic feature [HANZI] contains a list of Chinese characters (hanzi or kanji).  The feature [CONTENT] embodies the semantic representation of the sign.  [CATEGORY] carries values like [n] for noun, [v] for verb, [a] for adjective, [p] for preposition, etc.  The structural feature [STRUCT] contains information on the relation of the structure to its sub-constituents, to be presented in detail in section 3.3.

The features whose appropriate value must be the type [expected] are called expectation features.  They are the essential part of a lexicalist grammar as these features contain information about various types of potential structures in both syntax and morphology.  They specify various constraints on the expected daughter(s) of a sign for structural analysis.   The design of these expectation features and their appropriate type [expected] will be presented shortly in section 3.2.

The definition of [a_sign] illustrates the HPSG philosophy of mono-stratal analysis interleaving different components.  As seen, different components of Chinese grammar are contained in different feature structures for the general linguistic unit sign.  Their interaction is effected via the unification of relevant feature structures during various stages of analysis.  This will unfold as the solutions to the morpho-syntactic interface problems are presented in Chapter V and Chapter VI.  For illustration, the prefix 可 ke (-able) is used as an example in the following discussion.

As is known, the prefix ke- (-able) makes an adjective out of a transitive verb:  ke- + Vt --> A.  This lexicalized rule is contained in the CPSG95 entry for the prefix ke-, shown in (3-2).  Following the ALE notation, @ is used for macro, a shorthand mechanism for a pre-defined feature structure.[6]

As seen, the prefix ke- morphologically expects a sign with [CATEGORY vt].  An affix is analyzed as the head of a derivational structure in CPSG95 (see section 6.1 for discussion) and [CATEGORY] is a representative head feature to be percolated up to the mother sign via the corresponding morphological PS rule as formulated in (6-4) of section 6.2, this expectation eventually leads to a derived word with [CATEGORY a].  Like most Chinese adjectives, the derived adjective has an optional expectation for a subject NP to account for sentences like 这本书很可读 zhe (this) ben (CLA) shu (book) hen (very) ke-du (read-able): ‘This book is very readable’.  This syntactic optional expectation for the derivative is accommodated in the head feature [SUBJ].

Note that before any structural combination of ke- with other expected signs, ke- is a bound morpheme, a sign which has obligatory morphological expectation in [PREFIXING].  As a head for both the morphological combination ke+Vt and the potential syntactic combination NP+[ke+Vt], the interface between morphology and syntax in this case lies in the hierarchical structures which should be imposed.   That is, the morphological structure (derivation) should be established before its syntactic expected structure can be realized.  Such a configurational constraint is specified in the corresponding PS rules, i.e. the Subject PS Rule and The Prefix PS Rule.  It guarantees that the obligatory morphological expectation of ke- has to be saturated before the sign can be legitimately used in syntactic combination.

The interaction between morphology/syntax and semantics in this case is encoded by the information flow, i.e. structure-sharing indicated by the number index in square brackets, between the corresponding feature structures inside this sign.  The semantic compositionality involved in the morphological and syntactic grouping is represented like this.  There is a semantic predicate marked as [-able] (for worthiness) in the content feature [RELN];  this predicate has an argument which is co-indexed by [1] with the semantics of the expected Vt.  Note that the syntactic subject of the derived adjective, say ke-du (read-able) or ke-chi (eat-able), is the semantic (or logical) object of the stem verb, co-indexed by [2] in the sample entry above.  The head feature [CONTENT] which reflects the semantic compositionality will be percolated up to the mother sign when applicable morphological and syntactic PS rules take effect in structure building.

In summary, embodied in CPSG95 is a mono-stratal grammar of morphology and syntax within the same formalism.  Both morphology and syntax use same data structure (typed feature structure) and mechanisms (unification, sort hierarchy, PS rules, lexical rules, macros).   This design for Chinese grammar is original and is shown to be feasible in the CPSG95 experiments on various Chinese constructions.  The advantages of handling morpho-syntactic interface problems under this design will be demonstrated throughout this dissertation.

3.2. Expectation Feature Structures

This section presents the design of the expectation features in CPSG95.  In general, the expectation features contain information about various types of potential structures of the sign.  In CPSG95, various constraints on the expected daughter(s) of a sign are specified in the lexicon to drive both morphological and syntactic structural analysis.  This provides a favorable basis for interleaving Chinese morphology and syntax in analysis.

The expected daughter in CPSG95 is defined as one of the following grammatical constituents:  (i) subject in the feature [SUBJ];  (ii) first complement in the feature [COMP0_LEFT] or [COMP1_RIGHT];  (iii) second complement in [COMP2_RIGHT];   (iv) head of a modifier in the feature [MOD_LEFT] or [MOD_RIGHT];   (v) stem of an affix in the feature [PREFIXING] or [SUFFIXING].[7]  The first four are syntactic daughters which will be investigated in sections 3.2.2 and 3.2.3.  The last one is the morphological daughter for affixation, to be presented in section 3.2.1.  All these features are defined on the basis of the relative word order of the constituents in the structure.  The hierarchy for the structure at issue resorts to the configurational constraints which will be presented in section 3.2.4.

3.2.1. Morphological Expectation

One key characteristic of the CPSG95 expectation features is the design of morphological expectation features to incorporate Chinese productive derivation.

It is observed that a Chinese affix acts as the head daughter of the derivative in terms of expectation (see section 6.1 for more discussion).   An affix can lexically define what stem to expect and can predict the derivation structure to be built.  For example, the suffix 性 –xing demands that it combine with a preceding adjective to make an abstract noun, i.e. A+-xing --> N.  This type of information can be easily captured by the expectation feature structure in the lexicon, following the practice of the HPSG treatment of the syntactic expectation such as subcategorization and modification.

In the CPSG95 lexicon, each affix entry is encoded to provide the following derivation information:   (i) what type of stem it expects;  (ii) whether it is a prefix or suffix to decide where to look for the expected stem;  (iii) what type of (derived) word it produces.  Based on this lexical information, the general grammar only needs to include two PS rules for Chinese derivation:  one for prefixation, one for suffixation.  These rules will be formulated in Chapter VI (sections 6.2 and 6.3).  It will also be demonstrated that this lexicalist design for Chinese derivation works for both typical cases of affixation and for some difficult cases such as ‘quasi-affixation’ and zhe-suffixation.

In summary, the morphological combination for productive derivation in CPSG95 is designed to be handled by only two PS rules in the general grammar, based on the lexical specification in [PREFIXING] and [SUFFIXING].  Essentially, in CPSG95, productive derivation is treated like a ‘mini-syntax’;[8]  it becomes an integrated part of Chinese structural analysis.

3.2.2. Syntactic Expectation

This section presents the design of the expectation features to represent Chinese syntactic relations.  It will be demonstrated that constraints like word order and function words are crucial to the formalization of syntactic relations.  Based on them, four types of syntactic relations can be defined, which are accommodated in six syntactic expectation feature structures for each head word.

There is no general agreement on how to define Chinese syntactic relations.  In particular, the distinction between Chinese subject and object has been a long debated topic (e.g. Ding 1953; L. Li 1986, 1990; Zhu 1985; Lü 1989).  The major difficulty lies in the fact that Chinese does not have inflection to indicate subject-verb agreement and nominative case or accusative case, etc.

Theory-internally, there have been various proposals that Chinese syntactic relations be defined on the basis of one or more of the following factors:  (i) word order (more precisely, constituent order);  (ii) the function words associated with the constituents;  (iii) the semantic relations or roles.  The first two factors are linguistic forms while the third factor belongs to linguistic content.

L. Li (1986, 1990) relies mainly on the third factor to study Chinese verb patterns. The constituents in his proposal are named as NP-agent (ming-shi), NP-patient (ming-shou), etc. This practice amounts to placing an equal sign between the syntactic relation and semantic relation.  It implies that the syntactic relation is not an independent feature.  This makes syntactic generalization difficult.

Other Chinese grammarians (e.g. Ding 1953; Zhu 1985) emphasize the factor of word order in defining syntactic relations.  This school insists that syntactic relations be differentiated from semantic relations.  More precisely, semantic relations should be the result of the analysis of syntactic relations.  That is also the rationale behind the CPSG95 practice of using word order and other constraints (including function words) in the definition of Chinese relations.

In CPSG95, the expected syntactic daughter in CPSG95 is defined as one of the following grammatical constituents:  (i) subject in the feature [SUBJ], typically an NP which is on the leftmost position relative to the head;  (ii) complements closer to the head in the feature [COMP0_LEFT] or [COMP1_RIGHT], in the form of an NP or a specific PP;  (iii) the second complement in [COMP2_RIGHT]: this complement is defined to be an XP (NP, a specific PP, VP, AP, etc.) farther away from the head than [COMP1_RIGHT] in word order;  (iv) head of a modifier in the feature [MOD_LEFT] or [MOD_RIGHT].  In this defined framework of four types of possible syntactic relations, for each head word, the lexicon is expected to specify the specific constraints in its corresponding expectation feature structures and map the syntactic constituents to the corresponding semantic roles in [CONTENT].  This is a secure way of linking syntactic structures and their semantic composition for the following reason.  Given a specific head word and a syntactic structure with its various constraints specified in the expectation feature structures, the decoding of semantics is guaranteed.[9]

A Chinese syntactic pattern can usually be defined by constraints from category, word order, and/or function words (W. Li 1996).  For example, NP+V, NP+V+NP, NP+PP(x)+NP, NP+V+NP+NP, NP+V+NP+VP, etc.  are all  such patterns.  With the design of the expectation features presented above, these patterns can be easily formulated in the lexicon under the relevant head entry, as demonstrated by the sample formulations given in (3-3) and (3-4).

The structure in (3-3) is a Chinese transitive pattern in its default word order, namely NP1+Vt+NP2.  The representation in (3-4) is another transitive pattern NP+PP(x)+Vt.  This pattern requires a particular preposition x to introduce its object before the head verb.

The sample entry in (3-5) is an example of how modification is represented in CPSG95.  Following the HPSG semantics principle, the semantic content from the modifier will be percolated up to the mother sign from the head-modifier structure via the corresponding PS rule.  The added semantic contribution of the adverb chang-chang (often) is its specification of the feature [FREQUENCY] for the event at issue.

3.2.3. Chinese Subcategorization

This section presents the rationale behind the CPSG95 design for subcategorization.  Instead of a SUBCAT-list, a keyword approach with separate features for each complement is chosen for representing the subcategorization information, as shown in the corresponding expectation features in section 3.2.2.  This design has been found to be a feasible alternative to the standard practice of HPSG relying on the list design of obliqueness hierarchy and SUBCAT Principle when handling subject and complements.

The CPSG95 design for representing subcategorization follows one proposal from Pollard and Sag (1987:121), who point out:  “It may be possible to develop a hybrid theory that uses the keyword approach to subjects, objects and other complements, but which uses other means to impose a hierarchical structure on syntactic elements, including optional modifiers not subcategorized for in the same sense.”  There are two issues for such a hybrid theory:  the keyword approach to representing subject and complements and the means for imposing a hierarchical structure.  The former is discussed below while the latter will be addressed in the subsequent section 3.2.4.

The basic reason for abandoning the list design is due to the lack of an operational definition of obliqueness which captures generalizations of Chinese subcategorization.  In the English version of HPSG (Pollard and Sag 1987, 1994), the obliqueness ordering is established between the syntactic notions of subject, direct object and second object (or oblique object).[10]  But these syntactic relations themselves are by no means universal.  In order to apply this concept to the Chinese language, there is a need for an operational definition of obliqueness which can be applied to Chinese syntactic relations.  Such a definition has not been available.

In fact, how to define Chinese subject, object and other complements has been one of the central debated topics among Chinese grammarians for decades (Lü 1946, 1989; Ding 1953; L. Li 1986, 1990; Zhu 1985; P. Chen 1994).  No general agreement for an operational, cross-theory definition of Chinese subcategorization has been reached.  It is often the case that formal or informal definitions of Chinese subcategorization are given within a theory or grammar.   But so far no Chinese syntactic relations defined in a theory are found to demonstrate convincing advantages of a possible obliqueness ordering, i.e. capturing the various syntactic generalizations for Chinese.

Technically, however, as long as subject and complements are formally defined in a theory, one can impose an ordering of them in a SUBCAT list.  But if such a list does not capture significant generalizations, there is no point in doing so.[11]  It has turned out that the keyword approach is a promising alternative once proper means are developed for the required configurational constraint on structure building.

The keyword approach is realized in CPSG95 as follows.  Syntactic constituents for subcategorization, namely subject and complements, are directly accommodated in four parallel features [SUBJ], [COMP0_LEFT], [COMP1_RIGHT] and [COMP2_RIGHT].

The feasibility of the keyword approach proposed here has been tested during the implementation of CPSG95 in representing a variety of structures.  Particular attention has been given to the constructions or patterns related to Chinese subcategorization.  They include various transitive structures, di-transitive structures, pivotal construction (jianyu-shi), ba-construction (ba-zi ju), various passive constructions (bei-dong shi), etc.  It is found to be easy to  accommodate all these structures in the defined framework consisting of the four features.

We give a couple of typical examples below, in addition to the ones in (3-3) and (3-4) formulated before, to show how various subcategorization phenomena are accommodated in the CPSG95 lexicon within the defined feature structures for subcategorization.  The expected structure and example are shown before each sample formulation in (3‑6) through (3-8) (with irrelevant implementation details left out).

Based on such lexical information, the desirable hierarchical structure on the related syntactic elements, e.g. [S [V O]] instead of [[S V] O], can be imposed via the configurational constraint based on the design of the expectation type.  This is presented in section 3.2.4 below.

3.2.4. Configurational Constraint

The means for the configurational constraint to impose a desirable hierarchical morpho-syntactic structure defined by a grammar is the key to the success of a keyword approach to structural constituents, including subject and complements from the subcategorization.  This section defines the sort hierarchy of the expectation type [expected].  The use of this design for flexible configurational constraint both in the general grammar and in the lexicon will be demonstrated.

As presented before, whether a sign has structural expectation, and what type of expectation a sign has, can be lexically decided:  they form the basis for a lexicalized grammar.  Four basic cases for  expectation are distinguished in the expectation type of CPSG95:  (i) obligatory: the expected sign must occur;  (ii) optional:  the expected sign may occur;  (iii) null:  no expectation;  (iv) satisfied: the expected sign has occurred.  Note that case (i), case (ii) and case (iii) are static information while (iv) is dynamic information, updated at the time when the daughters are combined into a mother sign.  In other words, case (iv) is only possible when the expected structure has actually been built.  In HPSG-style grammars, only the general grammar, i.e. the set of PS rules, has the power of building structures.  For each structure being built, the general grammar will set [satisfied] to the corresponding expectation feature of the mother sign.

Out of the four types, case (i) and case (ii) form a natural class,  named as [a_expected];  case (iii) and case (iv) are of one class named as [saturated].  The formal definition of the type [expected] is given (3-9].

(3-9.) Definition: sorted hierarchy for [expected]

expected: {a_expected, saturated}
a_expected: {obligatory, optional}
ROLE role
SIGN a_sign
saturated: {null, satisfied}

The type [a_expected] introduces two features:  [ROLE] and [SIGN].   [ROLE] specifies the semantic role which the expected sign plays in the structure.  [SIGN] houses various types of constraints on the expected sign.

The type [expected] is designed to meet the requirement of the configurational constraint.  For example, in order to guarantee that syntactic structures for an expecting sign are built on top of its morphological structures if the sign has obligatory morphological expectation, the following configurational constraint is enforced in the general grammar.  (The notation | is used for logical OR.)

(3-10.)         configurational constraint in syntactic PS rules

PREFIXING                    saturated | optional
SUFFIXING                    saturated | optional

The constraint [saturated] means that syntactic rules are permitted to apply if a sign has no morphological expectation or after the morphological expectation has been satisfied.  The reason why the case [optional] does not block the application of syntactic rules is the following.  Optional expectation entails that the expected sign may or may not appear.  It does not have to be satisfied.

Similarly, within syntax, the constraints can be specified in the Subject PS Rule:

(3-11.)         configurational constraint in Subject PS rule

COMP0_LEFT                 saturated | optional
COMP1_RIGHT              saturated | optional
COMP2                           saturated | optional

This ensures that complement rules apply before the subject rule does.  This way of imposing a hierarchical structure between subcategorized elements corresponds to the use of SUBCAT Principle in HPSG based on the notion of obliqueness.

The configurational constraint is also used in CPSG95 for the formal definition of phrase, as formulated below.

phrase macro

a_sign
PREFIXING saturated | optional
SUFFIXING saturated | optional
COMP1_LEFT saturated | optional
COMP1_RIGHT saturated | optional
COMP2 saturated | optional

Despite the notational difference, this definition follows the spirit reflected in the phrase definition given in Pollard and Sag (1987:69) in terms of the saturation status of the subcategorized complements.  In essence, the above definition says that a phrase is a sign whose morphological expectation and syntactic complement expectation (except for subject) are both saturated.  The reason to include [optional] in the definition is to cover phrases whose head daughter has optional expectation, for example, a verb phrase consisting of just a verb with its optional object omitted in the text.

Together with the design of the structural feature [STRUCT] (section 3.3), the sort hierarchy of the type [expected] will also enable the formal definition for the representation of the fundamental notion word (see Section 4.3 in Chapter IV).  Definitions such as @word and @phrase are the basis for lexical configurational constraints to be imposed on the expected signs when required.  For example, -xing (-ness) will expect an adjective stem with the word constraint and -zhe (-er) can impose the phrase constraint on the expected verb sign based on the analysis proposed in section 6.5.

3.3. Structural Feature Structure

The design of the feature [STRUCT] serves important structural purposes in the formalization of the CPSG95 interface between morphology and syntax.  It is necessary to present the rationale of this design and the sort hierarchy of the type [struct] used in this feature.

The design of [STRUCT struct] originates from the binary structural feature structure [LEX + | -] in the original HPSG theory (Pollard and Sag 1987).  However, in the CPSG95 definition, the type [struct] forms an elaborate sort hierarchy.   It is divided into two types at the top level:  [syn_dtr] and [no_syn_dtr].  A sub-type of [no_syn_dtr] is [no_dtr].  The CPSG95 lexicon encodes the feature [STRUCT no_dtr] for all single morphemes.[12]  Another sub-type of [no_syn_dtr] is [affix] (for units formed via affixation) which is further sub-typed into [prefix] and [suffix], assigned by the Prefix PS rule and Suffix PS Rule.  In syntax, [syn_dtr] includes sub-types like [subj], [comp] and [mod].  Despite the hierarchical depth of the type, it is organized to follow the natural classification of the structural relation involved.  The formal definition is given below.

(3-12.)         Definition: sorted hierarchy for [struct]

struct: {syn_dtr, no_syn_dtr}
syn_dtr: {subj, comp, mod}
comp: {comp0_left, comp1_right, comp2_right}
mod: {mod_left, mod_right}
no_syn_dtr: {no_dtr, affix}
affix: {prefix, suffix}

In CPSG95, [STRUCT] is not a (head) feature which percolates up to the mother sign;  its value is solely decided by the structure being built.[13]   Each PS rule, whether syntactic or morphological, assigns the value of the [STRUCT] feature for the mother sign, according to the nature of combination.  When morpheme daughters are combined into a mother sign word, the value of the feature [STRUCT] for the mother sign remains a sub-type of [no_syn_dtr].  But when some syntactic rules are applied, the rules will assign the value to the mother sign as a sub-type of [syn_dtr] to show that the structure being built is a syntactic construction.

The design of the feature structure [STRUCT struct] is motivated by the new requirement caused by introducing morphology into the general grammar of  CPSG95.  In HPSG, a simple, binary type for [LEX] is sufficient to distinguish lexical signs, i.e. [LEX +], from signs created via syntactic rules, i.e. [LEX -].  But in CPSG95, as presented in section 3.2.1 before, productive derivation is also accommodated in the general grammar.  A simple distinction between a lexical sign and a syntactic sign cannot capture the difference between signs created via morphological rules and signs created via syntactic rules.  This difference plays an essential role in formalizing the morpho-syntactic interface, as shown below.

The following examples demonstrate the structural representation through the design of the feature [STRUCT].  In the CPSG95 lexicon, the single Chinese characters like the prefix ke- (-able) and the free morphemes du (read), bao (newspaper) are all coded as [STRUCT no_dtr].   When the Prefix PS Rule combines the prefix ke- and the verb du into an adjective ke-du, the rule assigns [STRUCT prefix] to the newly built derivative.  The structure may remain in the domain of morphology as the value [prefix] is a sub-type of [no_syn_dtr].  However, when this structure is further combined with a subject, say, bao (newspaper) by the syntactic Subj PS Rule, the resulting structure [bao [ke-du]] (‘Newspapers are readable’) is syntactic, having [STRUCT subj] assigned by the Subj PS Rule;  in fact, this is a simple sentence.  Similarly, the syntactic Comp1_right PS Rules can combine the transitive verb du (read) and the object bao (newspaper) and assign for the unit du bao (read newspapers) in the feature [STRUCT comp1_right].  In general, when signs whose [STRUCT] value is a sub-type of [no_syn_dtr] combine into a unit whose [STRUCT] is assigned a sub-type of [syn_dtr], it marks the jump from the domain of morphology to syntax.  This is the way the interface of Chinese morphology and syntax is formalized in the present formalism.

The use of this feature structure in the definition of Chinese word will be presented in Chapter IV.  Further advantages and flexibility of the design of this structural feature structure and the expectation feature structures will be demonstrated in later chapters in presenting solutions to some long-standing problems at the morpho-syntactic interface.

3.4. Summary

The major design issues for the proposed mono-stratal Chinese grammar CPSG95 are addressed.  This provides a framework and means for formalizing the analysis of the linguistic problems at the morpho-syntactic interface.  It has been shown that the design of the CPSG95 expectation structures enables configuration constraints to be imposed on the structure hierarchy defined by the grammar.  This makes the keyword approach to Chinese subcategorization a feasible alternative to the list design based on the obliqueness hierarchy of subject and complements.

Within this defined framework of CPSG95, the subsequent Chapter IV will be able to formulate the system-internal, but strictly formalized definition of Chinese word.  Formal definitions such as @word and @phrase enable proper configurational constraints to be imposed on the expected signs when required.  This lays a foundation for implementing the proposed solutions to the morpho-syntactic interface problems to be explored in the remaining chapters.

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[1] More precisely, it is not ‘word’ order, it is constituent order, or linear precedence (LP) constraint between constituents.

[2]  L. Li (1986, 1990)’s definition on structural constituents does not involve word order.  However, his proposed definition is not an operational one from the angle of natural language processing.  He relies on the decoding of the semantic roles for the definitions of the proposed constituents like NP-agent (ming-shi), NP-patient (ming-shou), etc.  Nevertheless, his proposal has been reported to produce good results in the field of Chinese language teaching.  This seems to be understandable because the process of decoding semantic roles is naturally and subconsciously conducted in the mind of the language instructors/learners.

[3] Most linguists agree that Chinese has no inflectional morphology (e.g. Hockett 1958; Li and Thompson 1981; Zwicky 1987; Sun and Cole 1991).  The few linguists who believe that Chinese has developed or is developing inflection morphology include  Bauer (1988) and Dai (1993).  Typical examples cited as Chinese inflection morphemes are aspect markers le, zhe, guo and the plural marker men.

[4] A note for the notation: uppercase is used for feature and lowercase, for type.

[5] Phonology and discourse are not yet included in the definition.  The latter is a complicated area which requires further research before it can be properly integrated in the grammar analysis.  The former is not necessary because the object for CPSG95 is Written Chinese.   In the few cases where phonology affects structural analysis, e.g. some structural expectation needs to check the match of number of syllables, one can place such a constraint indirectly by checking the number of Chinese characters instead (as we know, a syllable roughly corresponds to a Chinese character or hanzi).

[6] The macro constraint @np in (3-2) is defined to be [CATEGORY n] and a call to another macro constraint @phrase to be defined shortly in Section 3.2.4.

[7] These expectation features defined for [a_sign] are a maximum set of possible expected daughters;  any specific sign may only activate a subset of them, represented by non-null value.

[8] This is similar to viewing morphology as ‘the syntax of words’ (Selkirk 1982; Lieber 1992; Krieger 1994).  It seems that at least affixation shares with syntax similar structural constraints on constituency and linear ordering in Chinese.  The same type of mechanisms (PS rules, typed feature structure for expectation, etc) can be used to capture both Chinese affixation and syntax (see Chapter VI).

[9] More precisely, the decoding of possible ways of semantic composition is guaranteed.  Syntactically ambiguous structures with the same constraints correspond to multiple ways of semantic compositionality.  These are expressed as different entries in the lexicon and the link between these entries is via corresponding lexical rules, following the HPSG practice. (W. Li 1996)

[10]  Borsley (1987) has proposed an HPSG framework where subject is posited as a distinct feature than other complements.  Pollard and Sag (1994:345) point out that “the overwhelming weight of evidence favors Borsley’s view of this matter”.

[11] The only possible benefit of such arrangement is that one can continue using the SUBCAT Principle for building complement structure via list cancellation.

[12] It also includes idioms whose internal morphological structure is unknown or has no grammatical relevance.

[13] The reader might have noticed that the assigned value is the same as the name of the PS rule which applies.  This is because there is correspondence between what type of structure is being built and what PS rule is building it.  Thus, the [STRUCT] feature actually records the rule application information.  For example, [STRUCT subj] reflects the fact that the Subj PS Rule is the most recently applied rule to the structure in point;  a structure built via the Prefix PS Rule has [STRUCT prefix] in place; etc.  This practice gives an extra benefit of the functionality of ‘tracing’ which rules have been applied in the process of debugging the grammar.  If there has never been a rule applied to a sign, it must be a morpheme carrying [STRUCT no_dtr] from the lexicon.

[Related]

PhD Thesis: Morpho-syntactic Interface in CPSG (cover page)

PhD Thesis: Chapter I Introduction

PhD Thesis: Chapter II Role of Grammar

PhD Thesis: Chapter III Design of CPSG95

PhD Thesis: Chapter IV Defining the Chinese Word

PhD Thesis: Chapter V Chinese Separable Verbs

PhD Thesis: Chapter VI Morpho-syntactic Interface Involving Derivation

PhD Thesis: Chapter VII Concluding Remarks

Overview of Natural Language Processing

Dr. Wei Li’s English Blog on NLP

The Morpho-syntactic Interface in a Chinese Phrase Structure Grammar

by

Wei Li

B.A., Anqing Normal College, China, 1982

M.A., The Graduate School of Chinese Academy of

Social Sciences, China, 1986

Thesis submitted in partial fulfillment of

the requirements for the degree of

DOCTOR OF PHILOSOPHY

in the Department

of

Linguistics

Morpho-syntactic Interface in a Chinese Phrase Structure Grammar

Wei Li 2000

SIMON FRASER UNIVERSITY

November 2000

All rights reserved. This work may not be reproduced in whole or in part, by photocopy or other means, without permission of the author.

Approval

Name:                         Wei Li

Degree:                       Ph.D.

Title of thesis:             THE MORPHO-SYNTACTIC INTERFACE IN

A CHINESE PHRASE STRUCTURE GRAMMAR

(Approved January 12, 2001)

Abstract

This dissertation examines issues related to the morpho-syntactic interface in Chinese, specifically those issues related to the following long-standing problems in Chinese Natural Language Processing (NLP): (i) disambiguation in Chinese word identification;  (ii) Chinese productive word formation;  (iii) borderline phenomena between morphology and syntax, such as Chinese separable verbs and ‘quasi-affixation’.

All these problems pose challenges to an independent Chinese morphology system or separate word segmenter.  It is argued that there is a need to bring in the syntactic analysis in handling these problems.

To enable syntactic analysis in addition to morphological analysis in an integrated system, it is necessary to develop a Chinese grammar that is capable of representing sufficient information from both morphology and syntax.  The dissertation presents the design of such a Chinese phrase structure grammar, named CPSG95 (for Chinese Phrase Structure Grammar).  The unique feature of CPSG95 is its incorporation of Chinese morphology in the framework of Head-Driven Phrase Structure Grammar.  The interface between morphology and syntax is then defined system internally in CPSG95 and uniformly represented using the underlying grammar formalism used by the Attribute Logic Engine.  For each problem, arguments are presented for the proposed analysis to capture the linguistic generality;  morphological or syntactic solutions are formulated based on the analysis.  This provides a secure approach to solving problems at the interface of Chinese morphology and syntax.

Dedication

To my daughter Tian Tian

whose babbling accompanied and inspired the writing of this work

And to my most devoted friend Dr. Jianjun Wang

whose help and advice encouraged me to complete this work

Acknowledgments

First and foremost, I feel profoundly grateful to Dr. Paul McFetridge, my senior supervisor.  It was his support that brought me to SFU and the beautiful city Vancouver, which changed my life.  Over the years,  he introduced me into the HPSG study, and provided me with his own parser for testing grammar writing.  His mentorship and guidance have influenced my research fundamentally.  He critiqued my research experiments and thesis writing in many facets, from the development of key ideas, selection of topics, methodology, implementation details to writing and presentation style.  I feel guilty for not being able to promptly understand and follow his guidance at times.

I would like to thank Dr. Fred Popowich, my second advisor.  He has given me both general academic guidance on research methodology and numerous specific comments for the thesis revision which have helped shape the present version of the thesis as it is today.

I am also grateful to Dr. Nancy Hedberg from whom I have taken four graduate courses, including the course of HPSG.  I have not only learned a lot from her lectures in the classroom, but have benefited greatly from our numerous discussions on general linguistic topics as well as issues in Chinese linguistics.

Thanks to Davide Turkato, my friend and colleague in the Natural Language Lab.  He is always there whenever I need help.  We have also shared many happy hours in our common circle of Esperanto club in Vancouver.

I would like to thank Dr. Ping Xue, Dr. Zita McRobbie, Dr. Thomas Perry, Dr. Donna Gerdts and Dr. Richard DeArmond for the courses I have taken from them.  These courses were an important part of my linguistic training at SFU.

For various help and encouragement I have got during my graduate studies, I should also thank all the faculty, staff and colleagues of the linguistics department and the Natural Language Lab of SFU, in particular, Rita, Sheilagh, Dr. Ross Saunders, Dr. Wyn Roberts, Dr. Murray Munro and Dr. Olivier Laurens.  I am particularly thankful to Carol Jackson, our Graduate Secretary for her years of help.  She is remarkable, very caring and responsive.

I would like to extend my thanks to all my fellow students and friends in the linguistics department of SFU, in particular, Dr. Trude Heift, Dr. Janine Toole, Susan Russel, Dr. Baoning Fu, Zhongying Lu, Dr. Shuicai Zhou, Jianyi Yu, Jean Wang, Cliff Burgess and Kyoung-Ja Lee.  We have had so much fun together and have had many interesting discussions, both academic and non-academic.  Today, most of us have graduated, some are professors or professionals in different universities or institutions.  Our linguistics department is not big, but it is such a nice department where faculty, staff and the graduate student body form a very sociable community.  I have truly enjoyed my graduate life in this department.

Beyond SFU, I would like to thank Dr. De-Kang Lin for the insightful discussion on the possibilities of integrated Chinese parsing back in 1995.  Thanks to Gerald Penn, one of the authors of ALE, for providing the powerful tool ALE and for giving me instructions on modifying some functions in ALE to accommodate some needs for Chinese parsing during my experiment in implementing a Chinese grammar.

I am also grateful to Dr. Rohini Srihari, my current industry supervisor, for giving me an opportunity to manage NLP projects for real world applications at Cymfony.  This industrial experience has helped me to broaden my NLP knowledge, especially in the area of statistical NLP and the area of shallow parsing using Finite State Transducers.

Thanks to Carrie Pine and Walter Gadz from US Air Force Research Laboratory who have been project managers for the Small Business Innovation Research (SBIR) efforts ‘A Domain Independent Event Extraction Toolkit’ (Phase II), ‘Flexible Information Extraction Learning Algorithm’ (Phase I and Phase II) and ‘Intermediate-Level Event Extraction for Temporal and Spatial Analysis and Visualization’ (Phase I and Phase II).  I have been Principal Investigator for these government funded efforts at Cymfony Inc. and have had frequent and extremely beneficial contact with them.  With these projects, I have had an opportunity to apply the skills and knowledge I have acquired from my Ph.D. program at SFU.

My professional training at SFU was made possible by a grant that Dr. Paul McFetridge and Dr. Nick Cercone applied for.  The work reported in this thesis was supported in the later stage  by a Science Council of B.C. (CANADA) G.R.E.A.T. award.  I am grateful to both my academic advisor Paul McFetridge and my industry advisor John Grayson, CEO of TCC Communications Corporation of Victoria, for assisting me in obtaining this prestigious grant.

I would not have been able to start and continue my research career without many previous helps I got from various sources, agencies and people in the last 15 years, for which I owe a big prayer of thanks.

I owe a great deal to Prof. Zhuo Liu and Prof. Yongquan Liu for leading me into the NLP area and supervising my master program in computational linguistics at CASS (Chinese Academy of Social Sciences, 1983-1986).  Their guidance in both research ideas and implementation details benefited me for life.  I am grateful to my former colleagues Prof. Aiping Fu, Prof. Zhenghui Xiong and Prof. Linding Li at the Institute of Linguistics of CASS for many insightful discussions on issues involving NLP and Chinese grammars.  Thanks also go to Ms. Fang Yang and the machine translation team at Gaoli Software Co. in Beijing for the very constructive and fruitful collaborative research and development work.  Our collaboration ultimately resulted in the commercialization of the GLMT English-to-Chinese machine translation system.

Thanks to Dr. Klaus Schubert, Dr. Dan Maxwell and Dr. Victor Sadler from BSO (Utrecht, The Netherlands) for giving me the project of writing a computational grammar of Chinese dependency syntax in 1988.  They gave me a lot of encouragement and guidance in the course of writing the grammar.  This work enabled me to study Chinese grammar in a formal and systematic way.  I have carried over this formal study of Chinese grammar to the work reported in this thesis.

I am also thankful to the Education Ministry of China, Sir Pao Foundation and British Council for providing me with the prestigious Sino-British Friendship Scholarship.  This scholarship enabled me to study computational linguistics at Centre for Computational Linguistics, UMIST, England (1992).  During my stay in UMIST, I had opportunities to attend lectures given by Prof. Jun-ichi Tsujii, Prof. Harold Somers and Dr. Paul Bennett.  I feel grateful to all of them for their guidance in and beyond the classroom.  In particular, I must thank Dr. Paul Bennett for his supervision, help and care.

I would like to thank Prof. Dong Zhen Dong and Dr. Lua Kim Teng for inviting and sponsoring me for a presentation at ICCC'96 in Singapore.  They are the leading researchers in the area of Chinese NLP.  I have benefited greatly from the academic contact and communication with them.

Thanks to anonymous reviewers of the international journals of  Communications of COLIPS, Journal of Chinese Information Processing, World Science and Technology and grkg/Humankybernetik.  Thanks also to reviewers of the International Conference on Chinese Computing (ICCC’96), North American Conference on Chinese Linguistics (NACCL‑9), Applied Natural Language Conference (ANLP’2000), Text Retrieval Conference (TREC-8), Machine Translation SUMMIT II, Conference of the Pacific Association for Computational Linguistics (PACLING-II) and North West Linguistics Conferences (NWLC).  These journals and conferences have provided a forum for publishing the NLP-related research work I and my colleagues have undertaken at different times of my research career.

Thanks to Dr. Jin Guo who has developed his influential theory of tokenization.  I have benefited enormously from exchanging ideas with him on tokenization and Chinese NLP.

In terms of research methodology and personal advice, I owe a great deal to my most devoted friend Dr. Jianjun Wang, Associate Professor at California State University, Bakersfield, and Fellow of the National Center for Education Statistics in US.  Although in a totally different discipline, there has never been an obstacle for him to understand the basic problem I was facing and to offer me professional advice.  At times when I was puzzled and confused, his guidance often helped me to quickly sort things out.  Without his advice and encouragement, I would not have been able to complete this thesis.

Finally, I wish to thank my family for their support.  All my family members, including my parents, brothers and sisters in China, have been so supportive and understanding.  In particular, my father has been encouraging me all the time.  When I went through hardships  in my pursuit,  he shared the same burden;  when I had some achievement,  he was as happy as I was.

I am especially grateful to my wife, Chunxi.  Without her love, understanding and support, it is impossible for me to complete this thesis.  I wish I had done a better job to have kept her less worried and frustrated.  I should thank my four-year-old daughter, Tian Tian.  I feel sorry for not being able to spend more time with her.  What has supported me all these years is the idea that some day she will understand that as a first-generation immigrant, her dad has managed to overcome various challenges in order to create a better environment for her to grow.

Approval                    ii

Abstract                    iii

Dedication                    iv

Acknowledgments                  v

Chapter I  Introduction                1

1.0. Foreword                1

1.1. Background                2

• Principle of Maximum Tokenization and Critical Tokenization            2

• Monotonicity Principle and Task-driven Segmentation            5

1.2. Morpho-syntactic Interface Problems        8

1.2.1. Segmentation ambiguity        8

1.2.2. Productive Word Formation        10

1.2.3. Borderline Cases between Morphology and Syntax              11

1.3. CPSG95:  HPSG-style Chinese Grammar in ALE    13

1.3.1. Background and Overview of CPSG95    14

1.3.2. Illustration              15

1.4. Organization of the Dissertation          16

Chapter II  Role of Grammar              18

2.0. Introduction                18

2.1. Segmentation Ambiguity and Syntax        19

2.1.1. Resolution of Hidden Ambiguity      19

2.1.2. Resolution of Overlapping Ambiguity    24

2.2. Productive Word Formation and Syntax      33

2.3. Borderline Cases and Grammar          37

2.4. Knowledge beyond Syntax            39

2.5. Summary                46

Chapter III  Design of CPSG95              48

3.0. Introduction                48

3.1. Mono-stratal Design of Sign          52

3.2. Expectation Feature Structures          57

3.2.1. Morphological Expectation        58

3.2.2. Syntactic Expectation          59

3.2.3. Chinese Subcategorization        63

3.2.4. Configurational Constraint        67

3.3. Structural Feature Structure          70

3.4. Summary                73

Chapter IV  Defining the Chinese Word          75

4.0. Introduction                75

4.1. Two Notions of Word            78

4.2. Judgment Methods              83

4.3. Formal Representation of Word          88

4.4. Summary                92

Chapter V  Chinese Separable Verbs            93

5.0. Introduction                93

5.1. Verb-object Idioms: V+N I            96

5.2. Verb-object Idioms: V+N II          107

5.3. Verb-modifier Idioms: V+A/V          116

5.4. Summary                122

Chapter VI  Morpho-syntactic Interface Involving Derivation    123

6.0. Introduction                123

6.1. General Approach to Derivation          125

6.2. Prefixation                127

6.3. Suffixation                130

6.4. Quasi-affixes                132

6.5. Suffix zhe (-er)              139

6.6. Summary                151

Chapter VII  Concluding Remarks            152

7.0. Summary                152

7.1. Contributions              154

7.2. Limitation                158

7.3. Final Notes                    159

BIBLIOGRAPHY                  161

APPENDIX I    Source Code of Implemented CPSG95      170

APPENDIX II  Source Code of Implemented CPSG95 Lexicon    208

APPENDIX III  Tested Results in Three Experiments Using CPSG95  229

[Related]

PhD Thesis: Morpho-syntactic Interface in CPSG (cover page)

PhD Thesis: Chapter I Introduction

PhD Thesis: Chapter II Role of Grammar

PhD Thesis: Chapter III Design of CPSG95

PhD Thesis: Chapter IV Defining the Chinese Word

PhD Thesis: Chapter V Chinese Separable Verbs

PhD Thesis: Chapter VI Morpho-syntactic Interface Involving Derivation

PhD Thesis: Chapter VII Concluding Remarks

Overview of Natural Language Processing

Dr. Wei Li’s English Blog on NLP