44
Introduction to Lexical Functional Grammar Mary Dalrymple, John Lowe, & Louise Mycock Centre for Linguistics and Philology Oxford University Konstanz, November/December 2012

Introduction to Lexical Functional Grammar

  • Upload
    others

  • View
    15

  • Download
    1

Embed Size (px)

Citation preview

Page 1: Introduction to Lexical Functional Grammar

Introduction to Lexical Functional GrammarMary Dalrymple, John Lowe, & Louise Mycock

Centre for Linguistics and PhilologyOxford University

Konstanz, November/December 2012

Page 2: Introduction to Lexical Functional Grammar

• “Semantic roles, syntactic constituents, and grammatical functionsbelong to parallel information structures of very different formalcharacter. They are related not by proof-theoretic derivation but bystructural correspondences, as a melody is related to the words of asong. The song is decomposable into parallel melodic and linguisticstructures, which jointly constrain the nature of the whole. In the sameway, the sentences of human language are themselves decomposableinto parallel systems of constraints – structural, functional, semantic,and prosodic – which the whole must jointly satisfy.” (Bresnan, 1990)

Page 3: Introduction to Lexical Functional Grammar

LFG

Two aspects of syntactic structure:

• Functional structure is the abstract functional syntactic organisation ofthe sentence, familiar from traditional grammatical descriptions,representing syntactic predicate-argument structure and functionalrelations like subject and object.

• Constituent structure is the overt, more concrete level of linear andhierarchical organisation of words into phrases.

Page 4: Introduction to Lexical Functional Grammar

LFG’s c-structure and f-structure

IP

NP

N

David

I′

VP

V′

V

greeted

NP

N

Chris

PRED ‘GREET〈SUBJ,OBJ〉’

SUBJ[

PRED ‘DAVID’]

OBJ[

PRED ‘CHRIS’]

Page 5: Introduction to Lexical Functional Grammar

Functional structure

PRED ‘GO〈SUBJ〉’

TENSE PAST

SUBJ

[PRED ‘DAVID’NUM SG

]

• PRED, TENSE NUM: attributes• ‘GO〈SUBJ〉’, DAVID, SG: values• PAST, SG: symbols (a kind of value)• ‘BOY’, ‘GO〈SUBJ〉’: semantic forms

Page 6: Introduction to Lexical Functional Grammar

F-structures

PRED ‘GO〈SUBJ〉’

TENSE PAST

SUBJ

[PRED ‘DAVID’NUM SG

]

ADJ{[

PRED ‘QUICKLY’]}

An f-structure can be the value of an attribute. Attributes with f-structurevalues are the grammatical functions: SUBJ, OBJ, OBJθ, COMP, XCOMP, ...

Page 7: Introduction to Lexical Functional Grammar

F-structures

PRED ‘GO〈SUBJ〉’

TENSE PAST

SUBJ

[PRED ‘DAVID’NUM SG

]

ADJ{[

PRED ‘QUICKLY’]}

A set of f-structures can also be a value of an attribute.

Page 8: Introduction to Lexical Functional Grammar

Sets of f-structures

PRED ‘GO〈SUBJ〉’

TENSE PAST

SUBJ

[PRED ‘DAVID’

]

[PRED ‘GEORGE’

]

ADJ{[

PRED ‘QUICKLY’]}

Sets of f-structures represent:

• adjuncts (there can be more than one adjunct) or• coordinate structures (there can be more than one conjunct)

Page 9: Introduction to Lexical Functional Grammar

C- and F-Structure

V

greeted

[PRED ‘GREET〈SUBJ,OBJ〉’

TENSE PAST

φ function relates c-structure nodes to f-structures.

(Function: Every c-structure node corresponds to exactly one f-structure.)

Page 10: Introduction to Lexical Functional Grammar

Constraining the c-structure/f-structure correspondence

V′

V

yawned

[PRED ‘YAWN〈SUBJ〉’

TENSE PAST

V′ −→ V

Page 11: Introduction to Lexical Functional Grammar

Local F-Structure Reference

V′

V

yawned

[PRED ‘YAWN〈SUBJ〉’

TENSE PAST

V′ −→ V

the current c-structure node (“self”): ∗the immediately dominating node (“mother”): ∗̂

the c-structure to f-structure function: φ

Page 12: Introduction to Lexical Functional Grammar

Rule Annotation

V′

V

yawned

[PRED ‘YAWN〈SUBJ〉’

TENSE PAST

V′ −→ Vφ(∗̂) = φ(∗)

mother’s (V′’s) f-structure = self’s (V’s) f-structure

Page 13: Introduction to Lexical Functional Grammar

Simplifying the Notation

φ(∗̂) (mother’s f-structure) = ↑φ(∗) (self’s f-structure) = ↓

V′

V

yawned

[PRED ‘YAWN〈SUBJ〉’

TENSE PAST

V′ −→ V↑ = ↓

mother’s f-structure = self’s f-structure

Page 14: Introduction to Lexical Functional Grammar

Using the Notation

V′ −→ V↑ = ↓

mother’s f-structure = self’s f-structure

V′

V↑ = ↓

Page 15: Introduction to Lexical Functional Grammar

Using the Notation

V′ −→ V↑ = ↓

mother’s f-structure = self’s f-structure

V′

V↑ = ↓

Page 16: Introduction to Lexical Functional Grammar

Using the Notation

V′ −→ V↑ = ↓

mother’s f-structure = self’s f-structure

V′

V↑ = ↓

Page 17: Introduction to Lexical Functional Grammar

Using the Notation

V′ −→ V↑ = ↓

mother’s f-structure = self’s f-structure

V′

V↑ = ↓

[ ]

Page 18: Introduction to Lexical Functional Grammar

More rules

V′ −→ Vφ(∗̂) = φ(∗)

NP(φ(∗̂) OBJ) = φ(∗)

mother’s f-structure’s OBJ = self’s f-structure

In simpler form:

V′ −→ V↑ = ↓

NP(↑ OBJ) = ↓

Page 19: Introduction to Lexical Functional Grammar

Using the Notation

V′ −→ V↑ = ↓

NP(↑ OBJ) = ↓

V′

V NP

[OBJ [ ]

]

Page 20: Introduction to Lexical Functional Grammar

Terminal nodes

V

yawned

[PRED ‘YAWN〈SUBJ〉’

TENSE PAST

]

Expressible as:

V −→ yawned(↑ PRED) = ‘YAWN〈SUBJ〉’

(↑ TENSE) = PAST

Standard form:

yawned V (↑ PRED) = ‘YAWN〈SUBJ〉’(↑ TENSE) = PAST

Page 21: Introduction to Lexical Functional Grammar

Phrase structure rules: English

IP −→(

NP(↑ SUBJ) = ↓

) (I′

↑ = ↓

)

I′ −→(

I↑ = ↓

) (VP↑ = ↓

)

VP −→(

V↑ = ↓

)

NP −→(

N↑ = ↓

)

Page 22: Introduction to Lexical Functional Grammar

Lexical entries: English

yawned V (↑ PRED) = ‘YAWN〈SUBJ〉’(↑ TENSE) = PAST

David N (↑ PRED) = ‘DAVID’

(Standard LFG practice: include only features relevant for analysis underdiscussion.)

Page 23: Introduction to Lexical Functional Grammar

Analysis: English

IP

NP(↑ SUBJ) = ↓

N↑ = ↓

David(↑ PRED) = ‘DAVID’

I′

↑ = ↓

VP↑ = ↓

V↑ = ↓

yawned(↑ PRED) = ‘YAWN〈SUBJ〉’

(↑ TENSE) = PAST

Page 24: Introduction to Lexical Functional Grammar

Analysis: English

IP

NP(↑ SUBJ) = ↓

N↑ = ↓

David(fn PRED) = ‘DAVID’

I′

↑ = ↓

VP↑ = ↓

V↑ = ↓

yawned(↑ PRED) = ‘YAWN〈SUBJ〉’

(↑ TENSE) = PAST

Page 25: Introduction to Lexical Functional Grammar

Analysis: English

IP

NP(↑ SUBJ) = ↓

Nfnp = fn

David(fn PRED) = ‘DAVID’

I′

↑ = ↓

VP↑ = ↓

V↑ = ↓

yawned(↑ PRED) = ‘YAWN〈SUBJ〉’

(↑ TENSE) = PAST

Page 26: Introduction to Lexical Functional Grammar

Analysis: English

IP

NP(fip SUBJ) = fnp

Nfnp = fn

David(fn PRED) = ‘DAVID’

I′

↑ = ↓

VP↑ = ↓

V↑ = ↓

yawned(↑ PRED) = ‘YAWN〈SUBJ〉’

(↑ TENSE) = PAST

Page 27: Introduction to Lexical Functional Grammar

Analysis: English

IP

NP(fip SUBJ) = fnp

Nfnp = fn

David(fn PRED) = ‘DAVID’

I′

↑ = ↓

VP↑ = ↓

V↑ = ↓

yawned(fv PRED) = ‘YAWN〈SUBJ〉’

(fv TENSE) = PAST

Page 28: Introduction to Lexical Functional Grammar

Analysis: English

IP

NP(fip SUBJ) = fnp

Nfnp = fn

David(fn PRED) = ‘DAVID’

I′

↑ = ↓

VP↑ = ↓

Vfvp = fv

yawned(fv PRED) = ‘YAWN〈SUBJ〉’

(fv TENSE) = PAST

Page 29: Introduction to Lexical Functional Grammar

Analysis: English

IP

NP(fip SUBJ) = fnp

Nfnp = fn

David(fn PRED) = ‘DAVID’

I′

↑ = ↓

VPfi′ = fvp

Vfvp = fv

yawned(fv PRED) = ‘YAWN〈SUBJ〉’

(fv TENSE) = PAST

Page 30: Introduction to Lexical Functional Grammar

Analysis: English

IP

NP(fip SUBJ) = fnp

Nfnp = fn

David(fn PRED) = ‘DAVID’

I′

fip = fi′

VPfi′ = fvp

Vfvp = fv

yawned(fv PRED) = ‘YAWN〈SUBJ〉’

(fv TENSE) = PAST

Page 31: Introduction to Lexical Functional Grammar

Solving the Description

(fip SUBJ) = fnpfnp = fn(fn PRED) = ‘DAVID’fip = fi′

fi′ = fvpfvp = fv(fv PRED) = ‘YAWN〈SUBJ〉’(fv TENSE) = PAST

fipfi′

fvpfv

PRED ‘YAWN〈SUBJ〉’

TENSE PAST

SUBJfnpfn

[PRED ‘DAVID’

]

Page 32: Introduction to Lexical Functional Grammar

Final result

IP

NP(fip SUBJ) = fnp

Nfnp = fn

David(fn PRED) = ‘DAVID’

I′

fip = fi′

VPfi′ = fvp

Vfvp = fv

yawned(fv PRED) = ‘YAWN〈SUBJ〉’

(fv TENSE) = PAST

PRED ‘YAWN〈SUBJ〉’

TENSE PAST

SUBJ[

PRED ‘DAVID’]

Page 33: Introduction to Lexical Functional Grammar

Semantics in LFG

IP

NP

N′

N

John

I′

VP

V′

V

married

NP

N′

N

Rosa

PRED ‘MARRY〈SUBJ,OBJ〉’

SUBJ[

PRED ‘JOHN’]

OBJ[

PRED ‘ROSA’]

Meaning: marry(john, rosa)

How is this meaning composed?

Page 34: Introduction to Lexical Functional Grammar

Glue: Composing meanings via deduction

Glue (Asudeh, 2004, 2012; Dalrymple, 1999, 2001): Meaning assemblyand linear logic

• Logic of meanings (semantic level):the level of meanings of utterances and phrases

• Logic for composing meanings (‘glue’ level):the level responsible for assembling the meanings of parts to get themeaning of the whole

Page 35: Introduction to Lexical Functional Grammar

Meanings

Meanings are expressions like David, yawn(David), yawn ...

Function: when applied to an argument, yields a unique value.

yawn: applied to David, yields “true”.applied to Fred, yields “true”.applied to George, yields “false”....

Function application:

yawn applied to David = yawn(David)

Page 36: Introduction to Lexical Functional Grammar

Application and abstraction

Lambda abstraction:

λX.P represents a function from entities represented by X to entitiesrepresented by P .

Usually, the expression P contains at least one occurrence of the variableX, and we say that these occurrences are bound by the λ lambdaoperator.

Function application:

[λX.P ](a)

The function λX.P is applied to the argument a.

Equivalent to the expression that results from replacing all occurrences ofX in P with a.

Example: [λX.yawn(X)](David) ≡ yawn(David)

Page 37: Introduction to Lexical Functional Grammar

Meaning contributions

PRED ‘MARRY〈SUBJ,OBJ〉’

SUBJ[

PRED ‘JOHN’]

OBJ[

PRED ‘ROSA’]

• The word John contributes the meaning john.

• The word Rosa contributes the meaning rosa.

• The word married contributes meaning assembly instructions of thefollowing form: When given a meaning x for my subject and a meaningy for my object, I produce a meaning marry(x, y) for my sentence.

Page 38: Introduction to Lexical Functional Grammar

Contribution of ‘John’

NP

N′

N

John

[PRED ‘JOHN’

]john:[ ]

• Every f-structure has a corresponding semantic structure, related to itby the projection function σ (represented by a dotted line).

• john:[ ] is a meaning constructor.

• In the lexicon: john:↑σ

Page 39: Introduction to Lexical Functional Grammar

Meaning assembly: Gluing meanings together

PRED ‘MARRY〈SUBJ,OBJ〉’

SUBJ [ ]

OBJ [ ]

λy .λx .marry(x, y):oσ−◦(sσ−◦mσ)

λy .λx .marry(x, y): a relation between two individuals x and y that holds ifx marries y

oσ−◦(sσ−◦mσ): If I am provided with the semantic structure of my objectand then the semantic structure of my subject, I produce the semanticstructure of the sentence.

In the lexicon: λy .λx .marry(x, y):(↑ OBJ)σ−◦((↑ SUBJ)σ−◦↑σ)

Page 40: Introduction to Lexical Functional Grammar

Proof rules

X : fσP : fσ −◦ gσ

P (X) : gσ

Page 41: Introduction to Lexical Functional Grammar

Meaning proof for ‘married Rosa’

X : fσP : fσ −◦ gσ

P (X) : gσ

rosa:oσ λy .λx .marry(x, y):oσ−◦(sσ−◦mσ)λx .marry(x, rosa):sσ−◦mσ

Page 42: Introduction to Lexical Functional Grammar

Meaning proof for ‘John married Rosa’

X : fσP : fσ −◦ gσ

P (X) : gσ

rosa:oσ λy .λx .marry(x, y):oσ−◦(sσ−◦mσ)λx .marry(x, rosa):sσ−◦mσ john:sσ

marry(john, rosa): mσ

Page 43: Introduction to Lexical Functional Grammar

Details are not important for theory of information structure andprosody

Our theory of meaning composition, to be explained in the following:

rosa:oσ λy .λx .marry(x, y):oσ−◦(sσ−◦mσ)λx .marry(x, rosa):sσ−◦mσ john:sσ

marry(john, rosa): mσ

In fact, however, the details won’t be important for our discussion ofinformation structure. We can use abbreviations like the following, whereRosa stands for any reasonable theory of the meaning of Rosa and how itcombines with the rest of the sentence:

Rosa marriedmarried-Rosa Johnmarry(john, rosa): mσ

Page 44: Introduction to Lexical Functional Grammar

Bibliography

Asudeh, Ash. 2004. Resumption as Resource Management . Ph.D.thesis, Stanford University.

Asudeh, Ash. 2012. The Logic of Pronominal Resumption. Oxford:Oxford University Press.

Bresnan, Joan. 1990. Parallel constraint grammar project. CSLICalendar, 4 October 1990, volume 6:3.

Dalrymple, Mary (editor). 1999. Semantics and Syntax in LexicalFunctional Grammar: The Resource Logic Approach. Cambridge, MA:The MIT Press.

Dalrymple, Mary. 2001. Lexical Functional Grammar , volume 34 ofSyntax and Semantics. New York: Academic Press.