Lexical Functional Grammar

Lexical Functional Grammar • History: • Joan Bresnan (linguist, MIT and Stanford) • Ron Kaplan (computational psycholinguist, Xerox PARC) • Around 1978

What is Linguistic Theory • Delimit the range of possible human languages. • What do all languages have in common? • Semantic roles, grammatical relations, pragmatic relations, some constituent structure; only subjects can be controllees in matrix coding as subject constructions; etc. • What are the ways in which they can differ from each other? • Relative prominence of grammatical or pragmatic relations: word order reflects grammatical relations in English and reflects focus (new information) in Hungarian; Topic takes precedence over subject in Chinese in determining antecedent of null pronouns; Subject is more prominent in English. • What never happens in a human language? • Make a question by saying the sentence backwards.

Universalist view of language • There is “a common organizing structure of all languages that underlies their superficial variations in modes of expression” (Bresnan) • E.g., Passives that look very different in different languages can be described by a universal passive rule. • The common organizing structure is part of human biology.

S VP’ NP VP Some differences between English and Warlpiri Aux V NP The two small children are chasing that dog. S NP AUX V NP NP NP Wita-jarra-rlu ka-pala wajili-pi-nyi yalumpu kurdu-jarra-rlu maliki. Small-DU-ERG pres-3duSUBJ chase-NPAST that.ABS child-DU-ERG dog.ABS

Possible word orders in Warlpiri that are not possible in English • *The two small are chasing that children dog. • *The two small are dog chasing that children. • *Chasing are the two small that dog children. • *That are children chasing the two small dog.

Non-configurational languages • Free word order. • May have discontinuous constituents. • Tests for constituency do not yield evidence for VP constituent.

Something that English and Warlpiri have in common • Lucy is hitting herself. • *Herself is hitting Lucy. • Napaljarri-rli ka-nyanu paka-rni Napaljarri-ERG PRES-REFL hit-NONPAST “Napaljarri is hitting herself.” • *Napaljarri ka-nyanu paka-rni Napaljarri.ABSPRES-REFL hit-NONPAST “Herself is hitting Napaljarri.”

S S VP’ VP’ NP VP NP VP Aux V NP Aux V NP What English and Warlpiri have in common according to Chomsky Deep structure English Surface Structure

S VP’ NP VP Aux V NP What English and Warlpiri have in common according to Chomsky Deep structure Warlpiri Surface Structure S NP Aux V NP NP NP

What English and Warlpiri have in common according to Bresnan • Same grammatical relations and semantic roles • SUBJECT: the two small children: AGENT • PREDICATE: are chasing • OBJECT: that dog: PATIENT • Different codings of grammatical relations: • English subject: NP immediately under S • Warlpiri subject: Ergative case marked NP (if verb is transitive)

Strength of Chomsky’s approach • Proposing that there is a VP in all languages explains why there are subject-object asymmetries in all languages.

Strength of Bresnan’s approach • Doesn’t propose non-existent VPs: • phrase structure is used for representing constituency • A different representation is used for grammatical relations

Challenges for Bresnan and Chomsky • Bresnan: • explain subject-object asymmetries in the absence of a VP • Explain in a principled way the range of possible coding properties of grammatical relations • Chomsky: • explain in a principled way how the words get scrambled out of VP; • The phrase structure tree has to represent both grammatical relations and constituent structure, which may conflict with each other.

VP VP V PP V NP OBL OBJ Levels of Representation in LFG [s [np The bear] [vp ate [np a sandwich]]] constituent structure Grammatical encoding SUBJ PRED OBJ functional structure Lexical mapping Agent eat patient thematic roles Eat < agent patient > lexical mapping SUBJ OBJ Grammatical Encoding For English!!! S NP SUBJ

A surprise • Syntax is not about the form (phrase structure) of sentences. • It is about how strings of words are associated with their semantic roles. • Phrase structure is only part of the solution. • Sam saw Sue • Sam: perceiver • Sue: perceived

Surprise (continued) • Syntax is also about how to tell that two sentences are thematic paraphrases of each other (same phrases filling the same semantic roles). • It seems that Sam ate the sandwich. • It seems that the sandwich was eaten by Sam. • Sam seems to have eaten the sandwich. • The sandwich seems to have been eaten by Sam.

How to associate phrases with their semantic roles in LFG • Starting from a constituent structure tree: • Grammatical encoding tells you how to find the subject. • The bear is the subject. • Lexical mapping tells you what semantic role the subject has. • The subject is the agent. • Therefore, the bear is the agent.

VP VP V PP V NP OBL OBJ Levels of Representation in LFG [s [np The sandwich ] [vp was eaten [pp by the bear]]] constituent structure Grammatical encoding SUBJ PRED OBL functional structure Lexical mapping patient eat agent thematic roles Eat < agent patient > lexical mapping OBL SUBJ Grammatical Encoding For English!!! S NP SUBJ

Active and Passive • Active: • Patient is mapped to OBJ in lexical mapping. • Passive • Patient is mapped to SUBJ in lexical mapping. • Notice that the grammatical encodings are the same for active and passive sentences!!!

Passive mappings • Starting from the constituent structure tree. • The grammatical encoding tells you that the sandwich is the subject. • The lexical mapping tells you that the subject is the patient. • Therefore, the sandwich is the patient. • The grammatical encoding tells you that the bear is oblique. • The lexical mapping tells you that the oblique is the agent. • Therefore, the bear is the agent.

How you know that the active and passive have the same meaning • In both sentences, the mappings connect the bear to the agent role. • In both sentences, the mappings connect the sandwich to the patient role (roll?) • In both sentences, the verb is eat.

S-bar S VP NP NP S V PP SUBJ OBJ OBL Levels of Representation in LFG [s-bar [np what ] [s did [np the bear] eat ]] constituent structure Grammatical encoding OBJ SUBJ PRED functional structure Lexical mapping patient agent eat thematic roles Eat < agent patient > lexical mapping SUBJ OBJ Grammatical Encoding For English!!!

Wh-question • Different grammatical encoding: • In this example, the OBJ is encoded as the NP immediately dominated by S-bar • Same lexical mappings are used for: • What did the bear eat? • The bear ate the sandwich.

Principles • Variability: • Phrase structures and grammatical encodings vary across languages. • Universality • Functional structures are largely invariant across languages.

Functional Structure SUBJ PRED ‘bear’ NUM sg PERS 3 DEF + PRED ‘eat< agent patient > SUBJ OBJ TENSE past OBJ PRED ‘sandwich’ NUM sg PERS 3 DEF -

Functional Structure • Pairs of attributes (features) and values • Attributes (in this example): SUBJ, PRED, OBJ, NUM, PERS, DEF, TENSE • Values: • Atomic: sg, past, +, etc. • Feature structure: [num sg, pred `bear’, def +, person 3] • Semantic form: ‘eat<subj ob>’, ‘bear’, ‘sandwich’

Semantic Forms • Why are they values of a feature called PRED? • In some approaches to semantics, even nouns like bear are predicates (function) that take one argument and returns true or false. • Bear(x) is true when the variable x is bound to a bear. • Bear(x) is false when x is not bound to a bear.

Why is it called a Functional Structure? • X squared • 1 • 4 • 9 • 16 • 25 Each feature has a unique value. Also, another term for grammtical relation is grammatical function. features values

We will use the terms functional structure, f-structure and feature structure interchangeably.

Give a name to each function f1 SUBJ PRED ‘bear’ NUM sg PERS 3 DEF + PRED ‘eat< agent patient > SUBJ OBJ TENSE past OBJ PRED ‘sandwich’ NUM sg PERS 3 DEF - f2 f3

How to describe an f-structure • F1(TENSE) = past • Function f1 applied to TENSE gives the value past. • F1(SUBJ) = [PRED ‘bear’, NUM sg, PERS 3, DEF +] • F2(NUM) = sg

Descriptions can be true or false • F(a) = v • Is true if the feature-value pair [a v] is in f. • Is false if the feature-value pair [a v] is not in f.

This is the notation we really use • (f1 TENSE) = past • Read it this way: f1’s tense is past. • (f1 SUBJ) = [PRED ‘bear’, NUM sg, PERS 3, DEF +] • (f2 NUM) = sg

Chains of function application • (f1 SUBJ) = f2 • (f2 NUM) = sg • ((f1 SUBJ) NUM) = sg • Write it this way. (f1 SUBJ NUM) = sg • Read it this way. “f1’s subject’s number is sg.”

More f-descriptions • (f a) = v • f is something that evaluates to a function. • a is something that evaluates to an attribute. • v is something that evaluates to a function, symbol, or semantic form. • (f1 subj) = (f1 xcomp subj) • Used for matrix coding as subject. A subject is shared by the main clause and the complement clause (xcomp). • (f1 (f6 case)) = f6 • Used for obliques

SUBJ PRED ‘lion’ NUM pl PERS 3 PRED ‘seem < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ OBJ PRED ‘forest’ NUM sg PERS 3 DEF + S NP VP N V VP-bar COMP VP V PP P NP DET N Lions seem to live in the forest

SUBJ PRED ‘lion’ NUM pl PERS 3 PRED ‘seem < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ OBJ PRED ‘forest’ NUM sg PERS 3 DEF + f1 f2 S n1 f3 n2 NP VP n4 n3 N V VP-bar n5 n6 f4 n7 COMP VP n8 f5 f6 V PP n10 n9 P NP n12 n11 DET N n13 n14 Lions seem to live in the forest

Lexical Functional Grammar