Galley: Article - 00226

Level 1 Colin Phillips, University of Maryland, College Park, Maryland, USA

CONTENTS Goals of syntactic theory Cross-language similarities and differences Fundamentals of syntactic theory Variants of syntactic theory Constraints on dependencies Challenges and future prospects

Syntactic theory aims to explain how people com- amassed a large database of findings about an bine words to form sentences, and how children ever more diverse set of languages. attain knowledge of sentence structure. The complexity of syntactic knowledge sharpens 0226.004 the problem of how language is learned. Research GOALS OF SYNTACTIC THEORY on has demonstrated that children know much of the of their lan- 0226.001 Syntactic theory aims to provide an account of guage before they are old enough to understand how people combine words to form sentences. A explicit instruction about grammar. Therefore, a common feature of all human languages is that primary challenge for syntactic theory has been to speakers draw upon a finite set of memorized understand how a child can learn any language, words and morphemes to create a potentially infin- relatively effortlessly, and without explicit instruc- ite set of sentences. This property of discrete infinity tion. Research on comparative syntax has met this allows speakers to express and understand count- challenge by seeking to characterize human lan- less novel sentences that have never been uttered guages in terms of universal syntactic properties, before, and hence forms the basis of the creativity which may reflect the child's innate knowledge, of human language. Syntactic theory is concerned and non-universal clusters of syntactic properties with what speakers know about how to form sen- that pattern together across languages, and hence tences, and how speakers acquire that knowledge. may be learned as a group. Thus, the study of 0226.002 For example, speakers of English know that comparative syntax and the study of language `dogs chase cats' and `cats chase dogs' are possible learning are closely related. sentences of English, but have different meanings. Speakers know that `chase dogs cats' is not a pos- sible sentence of the language, and that `cats dogs FUNDAMENTALS OF SYNTACTIC chase' is possible in specific discourse contexts, as THEORY in `cats, dogs chase, but mice, they flee'. Speakers' knowledge of possible word combinations is often Discrete Infinity referred to as the (mental) grammar. Almost all accounts of the discrete infinity property 0226.005 0226.003 An accurate model of a speaker's knowledge of of natural language syntax start from the notion his or her language should minimally be able to that sentences consist of more than just sequences generate all and only the possible sentences of the of words. In the minds of speakers and listeners, language. For this reason, syntactic theory is often sentences are hierarchically structured representa- known as . In the 1950s, early tions, in which words are grouped together to form attempts by and others to create phrases, which in turn combine to form larger explicit generative quickly revealed phrases. For example, a minimal sentence of Eng- that speakers' knowledge of syntax is a good deal lish, such as `John arrived', contains a subject and a more complex than had been anticipated. Research predicate, but the roles of subject and predicate on syntactic theory has relied primarily upon may be replaced by phrases of arbitrary complex- speakers' intuitive judgments about the well- ity. By representing possible subjects and predi- formedness (`') of sentences of their cates as noun phrases (NPs) and verb phrases (VPs) language. Since grammaticality judgments can be respectively, the structure of many possible sen- gathered relatively easily, syntactic theory has tences (S) can be captured. This basic `template' Galley: Article - 00226 2 Syntax

for sentences of English can be expressed as a tree structure, as in (1a), or as a phrase structure rule, as in (1b). Although the rules listed in (1±5) fall far short of 0226.008 the expressive power of English, even this small a. S fragment shows how natural language syntax uses finite means to generate infinitely many sen- tences. NP VP John arrived the man ate an apple Motivating Structures: Constituency {{the elderly janitor { looked at his watch { The syntactician's toolbox includes a number of 0226.009 b. S NP VP (1) structural tests that can be used as aids in diagnos- ing sentence structures, for example, which groups of words form constituents of sentences. These can 0226.006 Just as rules like S NP VP provide templates ! generally be conjuncts in coordinate structures, for sentences, templates can also be specified for as is shown for NPs and VPs in (6a, b). Other tests the internal structure of noun phrases, verb that show the constituency of VPs include substitu- phrases, and many other phrase-types. Even a tion of the expression `do so' for a VP (7a), and small number of and a fronting of the VP to a clause-initial position (7b). small lexicon can generate large numbers of sen- tences. With only the five phrase structure rules in a: Wallace fetched the cheese and the ‰NP Š ‰NP (2) and a 30-word lexicon (consisting of 10 nouns, crackers Š 10 determiners, and 10 verbs) 122,100 different sen- b: Wallace sliced the cheese and opened ‰VP Š ‰VP tences can be generated. the crackers 6 Š † S NP VP a: Wallace read the newspaper and ! ‰VP Š VP VNP Gromit did so too: ! ‰VP Š b: Wallace wanted to impress Wendolene , VP V ‰VP Š ! and impress Wendolene he did: 7 NP Det NP ‰VP Š † ! NP N 2 Constituency tests like those shown in (7) can be 0226.010 ! † used to demonstrate that prepositional phrases 0226.007 Rules that allow a phrase to be embedded inside (PPs) that are adjuncts (i.e. optional phrases) of another phrase of the same type are known as recur- VP recursively expand the VP, whereas PPs that sive rules. Coordination (3), modification (4), and are arguments of the verb (i.e. required phrases) do sentential complementation (5) all involve recur- not. (8) shows that when do so substitution applies sion. They can thus be invoked arbitrarily many to a VP containing an adjunct-PP, the PP may be times in a single sentence. Such rules increase the targeted or ignored by do so substitution. This indi- expressive power of the grammar from merely vast cates that there is a smaller VP-constituent that to clearly infinite. There are obviously practical excludes the adjunct-PP. In contrast, (9) shows limitations on the length and complexity of natur- that an argument-PP cannot be ignored by do so ally occurring sentences, but such limitations are substitution. If the argument-PP is `stranded' typically attributed to independent limitations on by substitution (9b), the result is ungrammatical attention and memory. (indicated by the asterisk). This indicates that NP NP Conj NP argument-PPs are contained within the smallest ! VP VP Conj VP 3 VP constituent. These contrasts motivate the VP- ! † structures shown in (10). Conj and ! a: Wallace read the newspaper before ‰VP‰VP Š VP VP PP breakfast , and Gromit did so too: ! Š ‰VP‰VP ŠŠ NP NP PP 4 b: Wallace read the newspaper before ‰VP‰VP Š ! † breakfast , and Gromit did so at Š ‰VP‰VP Š VP VS0 lunchtime 8 ! † S0 Comp S 5 ! † Comp that ! Galley: Article - 00226 Syntax 3

(13a±d) but are impossible when the negative ex- a: Wallace put the newspaper on the table , ‰VP Š pression fails to c-command the NPI (13e±h), be- and Gromit did so too: ‰VP Š cause the negative expression is embedded inside a b: *Wallace put the newspaper on the ‰VP subject NP. table , and Gromit did so on the floor: 9 Š † Adjunct PP : VP VP PP a: Wallance didn't find any cheese: ! Argument PP : VP V NP PP 10 b: Nobody found any cheese: ! † † VP VP c: Wallance didn't think that he would ever refuse cheese: d: Nobody thought that Wallance would ever VP PP V NP PP refuse cheese: put e: * The fact that Wallance didn't like the ‰NP V NP before the newspaper on cheese amazed anybody: Š read breakfast the table f: * The fact that nobody liked the cheese ‰NP Š the newspaper amazed anybody: g: * The person that Wallace didn't notice Adjunct PP Argument PP ‰NP Š thought that Gromit would ever return: h: * The person that nobody noticed thought ‰NP Š that Gromit would ever return: Motivating Structures: Hierarchy S S 0226.011 In addition to tools that show which groups of words form constituents, other tests diagnose the hierarchical relations among positions in a structure. NP VP NP VP A striking finding of syntactic research is that many nobody grammatical phenomena are sensitive to a struc- tural relationship known as c-command, which is ...any...... nobody...... any... similar to the logical notion of scope. A node c- commands its sister and any nodes contained c-command c-command fails (13) inside its sister. Thus, in the structure in (12), node B c-commands its sister, node E, and nodes F and G contained inside its sister. On the other Multiple Roles: Transformations hand, node C c-commands its sister, node D, and no others. In any sentence, each word or phrase occurs in a 0226.013 unique position in the linear sequence of words. C-Command However, many words and phrases appear to par- A node c-commands its sister and all nodes ticipate in multiple structural relations in the sen- dominated by its sister: 11 tence. A central concern of syntactic research since † the 1950s has been to understand how individual A phrases can assume multiple roles in a sentence. The multifunctionality of phrases has been most 0226.014 fully explored in the case of NPs. First, speakers thematic role BE represent the of each NP in a sentence. Agent thematic roles are canonically realized on subject NPs, theme thematic roles are canonically realized on direct object NPs, and thematic roles CDFG (12) such as goal, beneficiary,orlocation are canonically 0226.012 One syntactic phenomenon that is sensitive to realized inside PPs (14). the c-command relation involves Negative Polarity Wallace sent the flowers to Wendolene Items (NPIs), such as `anybody' or `ever', which are agent theme goal 14 only possible when they are c-commanded by an † appropriate licenser, typically a negative expres- However, it is important to distinguish thematic sion such as `not' or `nobody'. NPIs are possible roles from grammatical relations such as subject and when the negative expression c-commands the NPI object, since thematic roles can be realized in differ- Galley: Article - 00226 4 Syntax

ent grammatical relations. The theme argument of for each sentence, one structure each for thematic the underlined verb `steal' is realized as a direct role assignments, grammatical relations, and scope object in the active sentence in (15a), as a subject in relations. The thematic representation is typically the passive sentence in (15b), and as the subject of a known as the deep structure (or d-structure) of the higher clause in the raising construction in (15c). sentence, and it is related to the other levels of representation ± surface structure (or s-structure) a: The penguin stole the diamond: active and logical form (LF) ± by transformational pro- theme cesses which move NPs from thematic positions b: The diamond was stolen by the to positions associated with grammatical relations, penguin: passive and scope positions. This theme approach was proposed by Chomsky in the 1950s c: The diamond seemed to have and has been elaborated and modified by many been stolen: raising passive ‡ linguists since that time. theme 15 † (18) shows a sample transformational derivation 0226.018 of a wh-question. The NP `who' receives the theme 0226.015 It is also important to distinguish thematic roles and grammatical relations from the structural pos- thematic role as the sister of the verb in the itions in which NPs receive their scopal interpret- d-structure representation in (18a). In (18b) it ation. In English, the scope of wh-phrases is marked moves to subject position of the embedded passive by their surface position: they are positioned sen- clause. Finally, in (18c) it moves from subject pos- tence-initially in direct wh-questions (16a), and in ition to its clause-initial scope position. Following a clause-initial position of an embedded clause in now standard elaboration of the transformational indirect wh-questions (16b). approach, (18) represents the residue of movement as phonologically null elements known as traces (t). a: Which story did the teacher know that the children like? a: the announcer had been theme believed elected who direct object b: the announcer had been elected ti matrix scope believed whoi b: The teacher knew which story the children c: whoi did the announcer had been elected ti always like: believe ti theme 18 † direct object embedded scope 16 Some alternative approaches share with Trans- 0226.019 † formational Grammar the assumption that sen- 0226.016 In English the scope of quantified NPs such as tence structure representations consist of multiple `every boy' is not encoded in surface word order, levels, but deny that there is a derivational relation- with the consequence that sentences like (17) are ship among the levels of representation (e.g. Lex- scopally ambiguous. However, in other languages, ical Functional Grammar, Categorial Grammar). such as Hungarian and Japanese, the scope of Other approaches assume that the thematic, gram- quantificational NPs is often fixed by surface matical relation, and scope properties of an NP are word order. all represented in a single enriched phrase struc- ture, but that only one of these positions is nor- Some student answered every question mally encoded phonologically (e.g. Head-Driven correctly: : see further below). some > every: a single student got all the question correct every > some: for each question, there was at least Types of Dependencies one student who got it right 17 † Speakers' syntactic representations encode a var- 0226.020 iety of structural relations among words and 0226.017 Since speakers must distinguish for any NP a phrases. The most basic relations are the groupings representation of its thematic role, its grammatical of words and phrases that form hierarchical con- relation, and its scope, it is important to ask how stituent structures. These relations can be expressed these different structural positions are related to entirely in terms of sisterhood and dominance among one another. One well-known answer to this ques- phrase structure nodes. The discussion above has tion is that speakers represent multiple structures Galley: Article - 00226 Syntax 5

introduced a number of other syntactic relations, or Ross, it has been found that there are many syntac- dependencies. tic environments which wh-extraction cannot cross. 0226.021 The syntactic relation between a pronoun or re- Following Ross's terminology, the environments flexive and the NP from which it takes its reference that block extraction are known as islands, and re- is known as a binding dependency. Such dependen- strictions on extraction are known as island con- cies have been studied extensively under the rubric straints. of Binding Theory. Relative clauses create islands for extraction 0226.026 (23a), as do indirect questions (23b), complements a: Wallace likes himself local i i of NPs (23c), subjects (23d), and adjunct clauses b: Wallace thinks that Wendolene i (23e). Extraction from definite or specific NPs is likes him nonlocal i highly marked (24b±c), although indefinite NPs 19 create no such difficulties (24a). If a phrase is ex- † tracted from one conjunct of a coordinate structure, 0226.022 In VP-ellipsis constructions the VP in the second it must also be extracted from the other conjuncts conjunct is dependent on the VP in the first con- (25a±b). junct for its interpretation (20). Transformational analyses of wh-questions (21a) and relative clauses a: *Who did the court upset the voters who i ‰ (21b) treat the relationship between the wh-phrase favored t iŠ and the trace as a binding relation between a wh- b: *Who did Bill wonder whether his new i ‰ operator and a variable. outfit would shock t iŠ c: *What did Sarah believe the rumor that Ed i ‰ Wallace VP likes cheese i and Gromit does was willing to spend t ‰ : Š iŠ VP i too 20 d: *Who did the fact that the president ‰ Š † i ‰ nominated ti upset the opposition party? a: Whoi did the voters elect ti Š e: *What did Wallace eat the cheese while he i ‰ b: The man whoi the voters elected ti 21 was reading t 23 † iŠ † 0226.023 A leading question in research on referential de- Whoi did Sally hear a a= b ? the= c *Helen's pendencies involves how closely related the differ- † † † story about ti? 24 ent types of referential dependencies are: does each † type of dependency follow independent principles, a: *What did Gromit read the newspaper i ‰ Š or do they follow the same principles? and Wallace eat t ‰ iŠ b: What did Gromit read t i ‰ i Š and Wallaceeat t 25 CONSTRAINTS ON DEPENDENCIES ‰ iŠ † 0226.024 Wh-movement and related phenomena have been The examples in (22±25) raise the question of 0226.027 among the most extensively investigated topics in why wh-dependencies can be arbitrarily long as in syntactic research, giving rise to a wealth of find- (22), but not as in (23±25). Work on this question led ings. By virtue of their length, syntacticians can to the proposal that, contrary to appearances, all manipulate which structural positions participate wh-dependencies are local. If all wh-movement is in the wh-dependency, and which structural pos- local, proceeding one clause at a time, then appar- itions the dependency crosses. Wh-dependencies ent long-distance wh-movement turns out to be a have thus served as a kind of `magnifying glass' series of local movements, each one targeting a for the investigation of syntactic dependencies. landing site in the next higher CP (Complementizer 0226.025 Wh-dependencies can span many clauses, in fact Phrase), as in (26). If all wh-movement must be local, arbitrarily many clauses, and thus they are often then it follows that relative clauses and embedded referred to as unbounded dependencies. In (22), the wh-questions create islands, because these are cases wh-phrase has been extracted from a number of in which an intermediate landing site of movement embedded clauses, each of which is the complement is already filled (27a). (direct object) of the next higher verb. The best-known implementation of this proposal 0226.028 is the Subjacency Constraint, proposed by Chomsky Which candidate did the court fear that the i ‰ in the early 1970s. In its original formulation the public might conclude that the voters had ‰ constraint blocks any wh-dependency which spans elected t 22 iŠŠ † more than two bounding nodes, where the bounding However, in a tradition of research beginning with nodes are defined as NP and TP (Tense Phrase:a influential work in the late 1960s by John Robert Galley: Article - 00226 6 Syntax

more recent term for the `S' node, recognizing Tense is impossible if the complementizer is overt (29c). as the head of a clause). This formulation also ex- This constraint is known as the that-trace constraint, plains the complex NP constraint violation in (23c) and it has been observed in many languages, as and (27b). discussed further below.

Whoi do [ you think [CP ti that [ John said [CP ti that [ Mary met t−i]]]]] TP TP TP a: Whoi do you think ti that John met ti? b: Whoi do you think ti John met ti? c: *Who do you think t that t met John? 1 bounding node 1 bounding node 1 bounding node (26) i i i a. d: Whoi do you think ti ti met John? What do [ you wonder [ why [ John ate t t ]]] i TP CP j TP i j 29 † *2 bounding nodes 1 bounding node There are also differences in extraction possibilities between argument wh-phrases such as `what' and b. Whati did [TP Sarah believe [NP the rumor [CP tj that [TP Bill had said ti ]]]] `which books', and adjunct wh-phrases such as `why' and `how' (see Further Reading). *2 bounding nodes 1 bounding node A long-standing goal of syntactic research on 0226.031 (27) unbounded dependencies has been to uncover a 0226.029 The proposal that a long-distance wh-depend- set of general principles that can explain the full ency involves a sequence of local dependencies variety of constraints on wh-dependencies. Al- receives interesting support from a number of lan- though there have been many different attempts guages which show a syntactic residue of local to unify the constraints on movement, two obser- movement. In certain varieties of Spanish, for vations have been pervasive, and have featured in example, subject±auxiliary inversion occurs in many different theories. First, if movement is re- every clause in the path of wh-movement ((28): quired to be local, then it is subject to intervention compare this to the English translation, in which effects, when a required landing site of movement is inversion occurs only in the highest clause). occupied by another element. Second, movement paths that include noncomplement nodes (subjects a: Juan pensaba que Pedro le habia dicho que or adjuncts) are consistently more restricted than la revista habia publicado ya el articolo: paths that include only complement nodes (sisters Juan thought that Pedro him had told that of heads). the journal had published already the article `Juan thought that Pedro had told him that CROSS-LANGUAGE SIMILARITIES the journal had published the article AND DIFFERENCES already:0 A fully general theory of the mental representation 0226.032 b: Que pensaba Juan que le habia dicho Pedro of syntax clearly must handle the facts of all human que habia publicado la revista? languages. In addition, cross-linguistic investiga- What thought Juan that him had told Pedro tions are important to accounts of how natural that had published the journal language syntax is learnable. Universals of syntax, `What did Juan think that Pedro had told or principles, may be part of the child's innate en- him that the journal had published?' dowment, and thus not need to be learned. Non- c: *Que pensaba Juan que Pedro le habiadicho universal syntactic properties must also be learnable que la revista habia publicado? within the constraints imposed by the time and What thought Juan that Pedro him had told evidence available to the child. When a set of syn- that the journal had published 28 † tactic properties covaries across languages, it is pos- sible that the learner only needs to learn one 0226.030 The island constraints restrict the nodes that a member of the set of properties in order to draw wh-dependency may cross. All of the examples pre- appropriate conclusions about the entire set. Thus, sented so far involve extraction of a direct object an important goal of cross-linguistic syntax re- wh-phrase. In addition, subject and adjunct wh- search is to find clusters of covarying syntactic phrases in English are subject to tighter restrictions properties, or parameters. This Principles and Param- than object wh-phrases. For example, extraction of eters (P&P) approach to syntax has been most inten- an embedded direct object wh-phrase is possible, sively investigated in transformational approaches irrespective of whether the embedded clause con- to syntax but it can be applied equally well to other tains an overt complementizer `that' (29a, b). How- ever, extraction of an embedded subject wh-phrase Galley: Article - 00226 Syntax 7

syntactic approaches. (See Government±Binding Theory) The similarity between English and Mohawk is 0226.033 Research on comparative syntax has discovered striking, given how different the languages appear a number of striking cross-linguistic parallels be- on the surface. Furthermore, evidence from many tween languages that appear very different on the other languages suggests that Binding Condition C surface. An example from Mohawk serves as an is a universal of natural language syntax, which illustration. may be part of innate linguistic knowledge. Con- 0226.034 One constraint on pronouns in English is that sistent with this suggestion, studies by Stephen a pronoun cannot co-refer with an NP that it c- Crain and his colleagues have shown that children commands. This constraint (`Binding Condition exhibit knowledge of Binding Condition C by their C') accounts for the contrast between (30a) and third birthday, which is as early as it has been (30b). The pronoun inside the subject NP fails to possible to test this knowledge. This finding has c-command the direct object in (30a), thereby been replicated in children learning other lan- allowing co-reference. On the other hand, the sub- guages (e.g. Italian, Dutch, Russian). It is particu- ject pronoun c-commands the name inside the larly encouraging news for a child learner of object NP in (30b), thereby preventing co-reference. Mohawk that Binding Condition C need not be learned, since it is unlikely that the presence of a: The book that he bought offended John ‰NP i Š i the constraint could be guessed from the input to b: *He bought the book that offended i ‰NP the Mohawk child. Johni 30 Although syntactic research has uncovered 0226.036 Š † many universals of language, there are clearly 0226.035 Unlike English, which exhibits strict subject± many properties that vary across languages and verb±object (SVO) word order, Mohawk, an Iro- hence must be learned. The search for parametric quoian language spoken in Quebec and upstate clusters of syntactic properties has turned up a New York, exhibits free word order, allowing all number of cross-language correlations. The most six possible permutations of subject, verb, and useful correlations are those that link abstract object, and also allows `discontinuous constituents' (and hence difficult-to-observe) syntactic proper- in the form of split noun phrases (31). Based on ties with more easily observable syntactic prop- such properties, languages like Mohawk have erties. For example, the that-trace constraint sometimes been described as `nonconfigurational'. introduced above does not apply in all languages: However, Mark Baker has demonstrated that it applies in English (33a), but not in Italian (33b). Mohawk exhibits similar configurational asymmet- This is not easily inferred from the language input ries to English, as the contrast in (32) shows. This to children, since it is not easy to observe the absence contrast can be explained by Binding Condition C, of a particular construction. However, the avail- just as in English, provided that we attribute some ability of that-trace sequences correlates cross-lin- degree of underlying configurational structure to guistically with the availability of postverbal Mohawk sentences. subjects, which are readily observable in the input to the learner. Italian allows postverbal subjects Ne kike wa-hi-yeena-' ne kweeskwes (34b), but English does not (34a). This connection NE this FACT-1sS=MsO-catch-PUNC has been reinforced based on the study of many NE pig other languages. Therefore, the child learner may `I caught this pig:' 31 † be able to learn whether the that-trace constraint a: Wa-ho-nakuni-` applies in his language, by observing whether post- tsi Sak wa-hi-hrewaht-e' verbal subjects are available. FACT-NsS=MsO-anger-PUNC a: *Whoi did you say that ti has written this that Sak FACT-1sS=MsO-punish-PUNC book? `That I punished Sak made him mad:' i i b: Chii hai detto che ti ha scritto co-reference possible † questo libro? b: Wa-shako-hrori-` who have-you said that has written tsi Sak wa-hi-hrewaht-e0 this book FACT-MsS=FsO-tell-PUNC `Who did you say has written this book?' that Sak FACT-1sS=MsO-punish-PUNC 33 `Hei told her that I punished Saki:' † co-reference impossible 32 † † Galley: Article - 00226 8 Syntax

syntactic head, which is spelled out as the word a: *Have arrived many students `runs'. b: Hanno arrivato molti studenti: At the other end are approaches that assume 0226.040 have-3pl arrived many students much larger atoms, in the form of templates for `Many students have arrived:' 34 † phrases or even clauses. Construction Grammar and some versions of Tree Adjoining Grammar VARIANTS OF SYNTACTIC THEORY are examples of such approaches. Under these ap- proaches, the representation of idiomatic expres- 0226.037 Since the 1960s syntactic theory has undergone sions is little different from the representation of a number of changes, and has spawned a variety other types of phrases. Construction Grammar has of different grammatical theories, each with a dif- provided some insightful analyses of constructions ferent title, such as Relational Grammar (RG), that have been largely overlooked in mainstream Head-Driven Phrase Structure Grammar (HPSG), transformational syntax. Lexical-Functional Grammar (LFG), Categorial Despite disagreements about the size of the 0226.041 Grammar (CG), Government-Binding Theory (GB), atoms of syntax, there has been a quiet convergence Tree Adjoining Grammar (TAG), etc. While it is of opinion on the role of the atoms of syntax. In tempting to view these as monolithic alternatives, early generative theories it was standard to distin- to do so would be misleading. guish the terminal elements of syntax (i.e. lexical 0226.038 First, all approaches provide only fragments of a items) from the phrase structure rules that deter- full theory of grammatical knowledge; sometimes mine how the terminals combine. In most current these fragments only partially overlap between ap- theories this distinction has been eliminated, and proaches. Second, there are many fundamental the work once done by phrase structure rules is points of agreement between the different ap- replaced by a set of highly general conditions on proaches. Third, the differences among practition- how syntactic atoms combine. In these lexicalized ers of the same general framework can be as large grammars, information about the combinatorial as or even larger than the differences between possibilities of syntactic atoms is built into the lex- frameworks. The differences of opinion that engen- ical entries of the atoms themselves. Lexicalism is a der different `named' grammatical theories draw common feature both of theories that assume very greater attention, but they have no special status. small syntactic atoms and of theories that assume Therefore, rather than reviewing different named much larger syntactic atoms. grammatical theories, this section focuses on a se- lection of fundamental issues on which syntactic theories diverge. Types of Structural Dependencies A second issue involves the question of how syn- 0226.042 Syntactic Atoms and How They tactic elements enter into structural dependencies. Combine As a starting point, in a typical phrase structure grammar syntactic elements enter into two basic 0226.039 First, syntactic theories differ on the issue of what types of dependencies, illustrated in (35). First, are the `atoms' of syntax, that is, the pieces of sen- when syntactic elements enter into a sisterhood rela- tences that are stored in a speaker's long-term tion, this both forms a dependency between the two memory. At one extreme are certain versions of elements and creates a new syntactic constituent. Transformational Grammar (including the recent Constituents may participate in a variety of differ- ), which claim that the atoms of ent syntactic processes, such as coordination, syntax are smaller than words ± either morphemes movement, and ellipsis. On the other hand, many or individual syntactic features. Under this ap- syntactic dependencies do not involve the forma- proach, underlying are formed tion of new constituents, for example subject±verb by selecting a set of these atomic units, and com- agreement and reflexive binding. bining them based on highly general principles of structure-building. Under this approach, syntax is responsible even for the formation of word-sized units. For example, an inflected verb such as `runs' may be formed by independently selecting the verbal head `run' and the inflectional head [3rd person singular, present], and applying a transform- ation which combines them to form a complex Galley: Article - 00226 Syntax 9

allow the combinatorial requirements of a category VP TP TP to be satisfied in a different order (38). V NP NP TЈ NP TЈ cats cats eat cheese i Leo saw Elliot head−complement T VP dependency T VP are ------head−specifier dependency Constituent No constituent V NP NP (S\NP)/NP NP formed formed scratch themselvesi binding dependency ------function application S\NP (35) ------function application 0226.043 The phrase structure notions that create this div- S (37) ision among structural dependencies continue to dominate thinking about syntax, but there are a Leo saw and Eileen heard Elliot number of interesting alternative proposals that ------reduce or eliminate this distinction. First, Depend- NP (S\NP)/NP conj NP (S\NP)/NP NP

ency Grammars treat all syntactic dependencies in a ----- type raising ----- type raising parallel fashion, and do not single out constituent- S/(S\NP) S/(S\NP)

forming dependencies as special (36). ------function composition------function composition Dependency Grammar representation of S/NP S/NP argument and agreement relations 36 ------conjunction † S/NP

------function application S John saw Mary John thinks Mary left (38)

0226.044 Combinatory Categorial Grammars (CCG) also Multiple Roles: Alternatives to reduce the division of dependency types, but in Transformations the opposite manner from Dependency Grammars. All syntactic theories must address the fact that 0226.046 In CCG grammars, information about the elements individual syntactic elements can enter into a var- that a syntactic atom may combine with is encoded iety of different structural relations. In a multi- in enriched category labels. For example, an in- clause sentence, a single phrase may take scope in transitive verb such as `run' might have the one clause, be case-marked by the predicate of a category label S\NP, read as `a category which second clause, and receive a thematic role in a third combines with an NP to its left to form an S'. clause (39). Dependencies between syntactic sisters are formed by the rule of function application. Dependencies [which boy do you think [ seems [ to have been healed ]]] between non-sisters are also formed by function case application, thanks to the mediating effects of func- thematic role tion composition rules, which allow the combinator- scope (39) ial requirements of a syntactic atom to be passed up Since the 1950s and 1960s, transformational ap- 0226.047 through a series of larger units. proaches to syntax have famously argued that 0226.045 By virtue of their more uniform treatment of phrases can bear multiple syntactic roles because structural dependencies, both Dependency Gram- there are multiple syntactic levels of representa- mar and Combinatorial Categorial Grammars have tion, which are related to one another via move- led to innovative proposals about the treatment of ment through a series of different structural constituency phenomena. Whereas most phrase positions. As a result, a leading area of research structure grammars impose a clear boundary on on transformational syntax has been the investiga- which syntactic relations form constituents, DG tion of constraints on possible movement oper- and CCG do not. Therefore, these approaches ations, as outlined above. have been used to analyze syntactic phenomena The syntactic frameworks Lexical-Functional 0226.048 that do not fall straightforwardly under standard Grammar (LFG) and certain versions of Combinatory notions of constituency, such as `nonconstituent Categorial Grammar (CCG) share with Transform- coordination' involving subject±verb sequences. In ational Grammar the assumption that words and CCG, flexible constituency relations are made pos- phrases bear multiple roles because they appear in sible by the introduction of type raising rules, which multiple different levels of representation. These Galley: Article - 00226 10 Syntax

approaches diverge from Transformational Gram- efficiency are used to provide a functional motiv- mar in the respect that they do not assume that each ation for a set of formal grammatical constraints. different level is a hierarchical constituent struc- Both Optimality Theory and certain versions of the 0226.052 ture, or that the levels are related by movement Minimalist Program question the standard assump- transformations. LFG assumes independent levels tion that a grammatical sentence is a sentence that of a-structure (argument structure: representation violates no constraints. This characterization is re- of argument/thematic roles), f-structure (function placed in these approaches with the requirement structure: representation of subject, object, etc. that a well-formed sentence is the optimal candidate roles), and c-structure (constituent structure: sur- from a set of possible structures/derivations for face syntax). There are rules for mapping between that sentence. In other words, a sentence may be these levels, but the mappings are not assumed to deemed ungrammatical for the simple reason that be transformational. In some versions of CCG sep- there exists a better way of expressing the same arate representations of argument structure and sur- thing. face structure are posited. 0226.049 In Head-Driven Phrase Structure Grammar (HPSG) CHALLENGES AND FUTURE only one syntactic level of representation is as- PROSPECTS sumed. This single level of representation com- bines words and phrases into the surface constituent structure that is familiar from many Universal Grammar other syntactic theories. However, the terminal The Principles and Parameters approach to syntax, 0226.053 elements of these structures contain highly articu- which is compatible with any of the syntactic lated feature structures, which encode a great deal frameworks discussed above, aims to explain how of information about argument structure, phon- a child can attain rich knowledge of any language. ology, `moved' arguments, and so on. Whereas It does so by seeking universal syntactic principles transformational grammars use movement oper- and clusters of syntactic properties that covary ations to handle the multiple roles problem, the across languages. Syntactic research since the same work is done largely internal to individual 1970s has uncovered a wealth of cross-linguistic syntactic heads in HPSG. For example, a verbal findings, and a number of good candidates for head may encode the information that a wh-phrase, universals of syntax have been found. However, which is represented as the focus argument of the the search for parameters has met with mixed suc- clause, is to be treated as the filler of one of the slots cess. The prospect that each parametric cluster may in the verb's argument structure list. Constraints be linked to an easily observable surface property on movement operations in transformational ap- of the language appears to be viable, but parametric proaches must be replaced in nontransformational clusters of properties appear to be both narrower theories by related constraints on the relations and more numerous than originally expected. It between scope and argument slots. remains to be seen whether all of natural language syntax, including the idiosyncrasies of each lan- Causes of Ungrammaticality guage, can be handled in terms of a Principles and Parameters approach. 0226.050 Standard approaches to syntactic theory assume a set of syntactic atoms and a relatively small number of formal principles or constraints that determine The Unification Problem how these atoms may be combined to form sen- Syntactic theories are theories that aim to charac- 0226.054 tences. A sentence is assumed to be grammatical if terize the mental representations underlying know- it violates no constraints. An ungrammatical sen- ledge of language, and of how people acquire that tence is a sentence that violates one or more con- knowledge. However, most syntactic theories char- straints. Some variants of syntactic theory have acterize knowledge of which sentences are gram- explored broader notions of what causes a sentence matical and which sentences are ungrammatical, to be (un)grammatical. with few suggestions about how speakers success- 0226.051 Functional grammars typically emphasize the role fully access this knowledge in real-time speaking or of meaning or of communicative efficiency in understanding, or about how children acquire this determining the well-formedness of a sentence. knowledge. Even less is known about how to Such approaches typically do not appeal directly encode this knowledge in brain structures. The to semantics or processing efficiency to explain overall goals of syntactic theory may be signifi- ungrammaticality. Rather, semantics or processing Galley: Article - 00226 Syntax 11 cantly affected by findings in these areas. In add- C-command Structural relation that a node bears to its ition, a complete syntactic theory will have to pro- sister node and to any nodes contained within its sister. vide answers to questions about how sentence Constituent Set of elements in a syntactic structure that structures are learned, used in real time, and en- are exhaustively dominated by a single node. Discrete infinity Property of generating infinitely many coded in the brain. expressions by combining finitely many elements. Grammatical relation Cover term for a set of structural Further Reading notions which express the role of a phrase within a clause, e.g. subject, (direct) object. Baker M (2001) The Atoms of Language. New York: Basic Island constraints Constraints on the movement of wh- Books. phrases and related elements in Transformational Baltin M and Collins C (2000) Handbook of Contemporary Grammar. Syntactic Theory. Malden, MA: Blackwell. Principles and Parameters approach Attempt to de- Bresnan J (2000) Lexical Functional Grammar. Malden, MA: scribe cross-language variation in terms of a series of Blackwell. universals (`principles') and a series of clusters of re- Chomsky N (1995) The Minimalist Program. Cambridge, lated syntactic properties (`parameters'). MA: MIT Press. Recursive Property of a rule that allows a syntactic unit Culicover P (1997) Principles and Parameters. New York: to be embedded inside another unit of the same Oxford University Press. category. Radford A (1988) Transformational Grammar. Cambridge, Thematic role Semantic relation holding between a verb UK: Cambridge University Press. and its arguments, e.g. agent, theme, goal, instrument. Roberts I (1997) Comparative Syntax. London: Edward Transformational Grammar Theory of syntax that Arnold. posits a series of structural representations for different Sag I and Wasow T (2000) Syntactic Theory: A Formal aspects of each sentence, which are related to one Introduction. Stanford, CA: CSLI Publications. another by movement of words and phrases. Steedman M (2000) The Syntactic Process. Cambridge, MA: MIT Press.

Glossary Adjunct Optional element or phrase within a syntactic phrase, sometimes referred to as modifier.

Keywords: syntax; constituent structure; transformations; principles and parameters; language acquisition