LFG

Slides based on slides by: Kersti Börjars & Nigel Vincent

{k.borjars, n.vincent}@man.ac.uk

University of Manchester

Winter school in LFGJuly 4-8 2004

University of CanterburyChristchurch, New Zealand

Syntactic Formalisms, So Far

• Goal: Relate surface word order (represented as phrase structure) to predicate-argument structure (close to semantics, represented as dependency structure)

• TAG: trees combine to form phrase structure, record of derivation is dependency tree

• HPSG: graphs encode both in intertwined manner• LFG: have both trees side by side, and relate them

using special functional information

Types of information about linguistic units

• Syntactic structure = phrase structure, c-structurethe dog forms a constituent in (1)

• Functional information = dependency, f-structurethe dog is the subject in (1)(1) is in past tense

• Argument structure, a-structureeat takes two arguments

• Information structure• Phonetic structure• …

(1) The dog ate the rats.

Correspondence between dimensions

(1) The dog ate the rats.

(2) The rats were eaten by the dog.

subject

object

deep subject

deep object

dog

ratsFunction Deep

syntactic role

subject

object

deep subject

deep object

dog

ratsFunction Deep

syntactic role

Correspondence between dimensions

(1) The dog ate the rats.

(2) The rats were eaten by the dog.

subject

object

agent

theme

dog

ratsFunction Semantic role

subject

object

agent

theme

dog

ratsFunction Semantic role

Non-one-to-one correspondence Parallel correspondence approach

a-structure c-structure

f-structure

mapping relations

a-structure

Information relating to the thematic roles associated with a predicate

(3) a. tickle < agent, patient>b. like < experiencer, theme>

Lexical Mapping Theory maps the arguments onto f-structure.

Arguments are represented as features.

f-structure: attributes

Types of attributes:

Functional features

NUM

PERS

TENSE

…

Semantic feature PRED

Grammatical relations

SUBJ

OBJ

ADJUNCT

COMP

…

A feature value matrix: an unordered set of feature-value pair

f-structure:values

Types of values:

Atomic valueValue of the functional features: plu, past, 3, fem

Semantic form value of PRED

f-structure value of grammatical relations

f-structures are reasonably invariant across languages

f-structure:examples

(4)

PRED ' pro'PERS 3NUM sgGEND fem

she

(5)

PRED 'smile SUBJ '

SUBJPRED 'goal keeper'NUM sgDEF +

TENSE past

The goal keeper smiled.

Semantic feature

Semantic feature

Functional features

Grammatical relation

Functional feature

Sw hon

Sw Målvakten log.

smile past

goal keeper sg,def

SUBJ

c-structure

Category labelled trees

CategoriesLexical S, N, V, P, A, (Adv)

Functional C, I, D

Both endocentric (headed) and exocentric (non-headed) structures allowed

Cross linguistic variation

c-structure: functional categories

(7) a. The rats will eat the dog.b. Will the rats eat the dog?

English:

Special status of auxiliary verbs:

(9) IP

I’

I

NP

VP

will

(8) a. The rats ate the dog.b. *Ate the rats the dog?

c-structure: an interlude

(10) The rats ate the dog.

Principle of Economy of Expression:all phrase structure nodes are optional unless required byindependent principles(completeness, coherence, semantic expressivity)

(11) IP

I’NP

VP

the dog

V

ate

NP

The ratsI VP

c-structure: “head to head movement”

C-structure heads are f-structure heads:Xn

X

Complements of functional categories are f-structure co-heads:

F’

XP

Mapping between f-structure and c-structure

PRED 'eat SUBJ OBJ 'SUBJ PRED 'dog' OBJ PRED 'rat' TENSE past

IP

I’NP

VPThe dog

NPV

ate the rats

Position: Spec-IP

Position: sister of V

Case: nominative

Case: accusativeS

NP NP V

rattos canis devoravit

S

NP NP V

canis rattos devoravit

Mapping between f-structure and c-structure

SUBJ

OBJ

(12) IP

I’NP

VP

The NPV

ate

dog

D N

the rats

D N

f1

f9

f8f7

f6f5f4

f3f2

f10

(13) a. IP NPSUBJ =

I'=

VP V=

NPOBJ =

NP D=

N=

=I' VP

Basic lexical entries

the

dog

ate

rats

( DEF) = +

PERS = 3

PRED = 'dog'

NUM = sg

PRED = 'rat'

NUM = pl

PRED = 'eat SUBJ OBJ '

TENSE = past

Mapping between f-structure and c-structure

DEF PERS 3

PRED 'dog 'NUM = sg

f10

IP

I’NP

VP

The NPV

ate

(12)

SUBJ

OBJ

dog

D N

the rats

D N

f1

f9

f8f7

f6f5f4

f3f2

PRED 'eat SUBJ OBJ 'TENSE past

PRED 'rat 'NUM = pl

f1 SUBJ = f2

f1 = f3

f2 = f4

f2 = f5

f3 = f6

f6 = f7

f6 OBJ = f8

f8 = f9

f8 = f10

f4 DEF = +

f5 PRED = ‘dog’

f5 NUM = sg

f7 PRED = ‘eat <SUBJ OBJ>’

f7 TENSE = past

f9 DEF = +

f10 PRED = ‘rat’

f10 NUM = pl

DEF PERS 3

f4 PERS = 3

f9 PERS = 3

Mapping between f-structure and c-structure

SUBJ

f1

f2

f3

f4 f5

DEF

PRED 'dog'

NUM sg

OBJ

DEF

PRED 'rat '

NUM plf8 f9 f10

f7f6

PRED 'eat SUBJ OBJ '

TENSE past

f7 PRED = ‘eat <SUBJ OBJ>’

f1 SUBJ = f2

f1 = f3

f2 = f4

f2 = f5

f3 = f6

f6 = f7

f6 OBJ = f8

f8 = f9

f9 = f10

f4 DEF = +

f5 PRED = ‘dog’

f5 NUM = sg

f7 TENSE = past

f9 DEF = +

f10 PRED = ‘rat’

f10 NUM = pl

Mapping between f-structure and c-structure

SUBJ

f1

f2 f4 f5

DEF

PRED 'dog'

NUM sg

OBJ

DEF

PRED 'rat '

NUM plf8 f9 f10

PRED 'eat SUBJ OBJ '

TENSE past

eatpast

dogsg,def ratpl,def

SUBJ OBJ

Mapping between f-structure and c-structure

SUBJ

OBJ

(12) IP

I’NP

VP

The NPV

ate

dog

D N

the rats

D N

(13) a. IP NPSUBJ =

I'=

VP V=

NPOBJ =

NP D=

N=

=I' VP

eatpast

dogsg,def ratpl,def

SUBJ OBJ

Well-formedness conditions on f-structure

SUBJ

DEF

PRED 'dog'

NUM sg

OBJ

DEF

PRED 'rat '

NUM pl

PRED 'eat SUBJ OBJ '

TENSE past

Completeness condition:

Coherence condition:

(i) all argument functions specified in the value of the PRED feature must be present in the local f-structure, (ii) all arguments so specified must have a PRED value.

(i) all argument functions in an f-structure must be specified by their local PRED, (ii) all functions which have a PRED value must be arguments of the element which specifies them.

Functional uniqueness:

Any attribute has only one value

Well-formedness conditions on f-structure

(14) a. *Oscar tickled.

b. *Oscar tickled Sarah the dog’s tummy.

c. *The sky rained.

Incomplete

Incoherent

Incoherent

Well-formedness conditions on f-structure

(14) d. *Tickles her.

e. tickles

PRED = 'tickle SUBJ OBJ '

TENSE = npast

SUBJ NUM = sg

SUBJ PERS = 3

f.

PRED ' tickle SUBJ OBJTENSE npast

OBJPRED 'proi 'GEND fem... ...

SUBJNUM sgPERS 3

Coherent? Yes

Complete?

No, cf (ii), no PRED value for SUBJ

Well-formedness conditions on f-structure

(14) g. *They tickles her.

h. tickles

PRED = 'tickle SUBJ OBJ '

SUBJ NUM = sg

f.

PRED ' tickle SUBJ OBJTENSE npast

SUBJPRED ' proi 'NUM sg & pl

OBJPRED ' pro j 'NUM sg

Functional uniqueness violated

i. they

NUM = pl

j.

IP NPSUBJ

I'

c-structure: back to Latin

(10) a. Canis rattos devoravit.dog.NOM rat.ACC.PL eat.PERF.3SG

b. all orders in possible under right information structural conditions

(11) S

NP NP V

S

NP V NP

Etc.

Morphology builds f-structure:

CASE = nom SUBJ = (15) a.

b.

CASE = acc OBJ =

c-structure: back to Latin

CASE = nom SUBJ = (15) a.

b.

CASE = acc OBJ =

(16) S

NP NP V

canis rattos devoravit

PRED 'dog'CASE = nom

PRED 'rat 'CASE = acc

SUBJ

OBJ

More on functions

Grammatical relations

SUBJ

OBJ

ADJUNCT

COMP

…

Semantic feature PRED

Functional features

NUM

PERS

TENSE

…

More on functions

Non-argumentTOP

Discourse functionFOC

Argument

Core

SUBJ

OBJ

Non-discourse function

OBJ

Non-coreOBL

COMP

Non-argument ADJUNCT

Discourse functions

(17) a. Beans, I like.FOCUS

CP NPFOCUS=

C'=

b. In Spec-CP

c.

PRED 'like SUBJ OBJ 'FOCUS PRED 'beans' SUBJ PRED 'proi '

FOCUS OBJ

OBJ

DF GF

Incomplete?

Complete

Functional uncertainty

COMP function

(18) a. Oscar claimed that he liked LFG.

b. claim

PRED = 'claim SUBJ COMP '

c.

VP V=

CPCOMP=

VP

V CP

claimed that he liked LFG

COMP

PRED 'claim SUBJ OBJ 'SUBJ PRED 'Oscar'

COMP

PRED 'like SUBJ OBJ '

SUBJ PRED ' pro ' OBJ PRED ' LFG'

TENSE past

OBJ and OBL functions

Both OBJ and OBL are argument functions which can occur in the PRED feature of a verb.

In (19a), a book is OBJ restricted to the role of theme, hence it is an OBJTHEME.

A function subscripted with a is restricted to a certain thematic role.

In English, an OBL is always a PP, whereas an OBJ is an NP.

(19) a. Oscar gave Sarah a book.b. Oscar gave a book to Sarah.

The PP to Sarah in (19b), is restricted to having a recipient role, hence it is an OBLRECIP.

OBJ function

(19) The teacher bought Sarah a book.

Sarah is OBJ a book is OBJ

• Provide the lexical entry for bought and the other words;

• Provide the phrase structure rule that is required (remember that it does not have to be binary branching);

• Add annotations to the phrase structure rule;

• Draw the tree using the new rule and the ones we have used in the class;

• Add numbered f-structure variables to each node (f1, f2, etc);

• Write down the equations and solve them to give you the correct f-structure.

Unbounded Dependency Constructions

(1) Who do you think Mary thought John saw - ?

• The initial element who belongs to 2 clauses simultaneously

• Different function in each• What sort of relation exists between gap

and filler?– Constituent - based or f-structure based

generalizations– LFG: f-strucutre based generalizations

F- and c-structure

Discourse functions

(17) a. what did you see? FOCUS

CP NPFOCUS=

C'=

b.

In Spec-CP

FOCUS OBJ

DF GF

Identifying the Function• ( focus) = ( obj)• ( focus) = ( comp obj)• ( focus) = ( comp comp obj)• ( focus) = ( comp comp comp obj)• ( focus) = ( comp comp comp comp obj)• ( focus) = ( subj)• ( focus) = ( comp subj)• ( focus) = ( comp comp subj)• ( focus) = ( comp comp comp subj)• ( focus) = ( comp comp comp comp subj)

Functional Uncertainty

Reading

The main reading for this part comes from:

Falk, Yehuda 2001. Lexical-Functional Grammar. An introduction to parallel constraint-based syntax. Stanford, Ca: CSLI Publications.

Chapters 1-3

If you want to have some additional reading, try:

Bresnan, Joan (2001) Lexical Functional Syntax. Oxford: Blackwell. Chapters 1-4

Dalrymple, Mary (2001) Lexical Functional Grammar. [Syntax and Semantics 34]. New York: Academic Press. Chapters 1-5.