rec curs ion and sub categorization

8/3/2019 Rec Curs Ion and Sub Categorization

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Recursion &Recursion &

SubcategorizationSubcategorization

How to get a lot from a littleHow to get a lot from a little



Infinite trees...Infinite trees...



Is there a longest sentence?Is there a longest sentence?



Looking again at NounLooking again at Noun

PhrasesPhrases•• a womana woman arrivedarrived

•• a woman in a hata woman in a hat arrivedarrived

•• a woman in a hat with a big brima woman in a hat with a big brim arrivedarrived

•• a woman in a hat with a small childa woman in a hat with a small child

arrivedarrived

•• a woman in a hat with a small child in aa woman in a hat with a small child in a

beretberet arrivedarrived



a

Det

woman

N

NP



a

Det

woman

N

NP

in

P

a

Det

hat

N

NPPP



a

Det

woman

NNP in

P

a

Det

hat

N

NP

PP

NP PP

NP



a

Det

woman

N

in

P

aDet

hatN

NP

PPNP

NP



a

Det

woman

N

in

P

aDet

hatN

NP

PPNP

NP What about

expanding t his

NP?



a

Det

woman

N

in

P

aDet

hatN

NP

PPNP

NP ... or t his one?



a

Det

woman

N

in

P

aDet

hatN

NP

PPNP

NP

... or t his one?



a

Det

woman

N

in

P

aDet

hatN

NP

PPNP

NP So let ’s t ry

t his...



a

Det

woman

N

NP

with

P

a

Det

child

N

NP

PP

NP

in

P

a

Det

hat

N

NP

PP

NP



a

Det

woman

N

in

P

aDet

hatN

NP

PPNP

NP

... now t his...

NP



a

Det

woman

N

NP

in

P

a

Det

hat

N

NP

with

P

a

Det

big

AdjAdjP

brimN

N

NP

PP

NP

PP

NP



a

Det

woman

N

in

P

aDet

hatN

NP

PPNP

NP ... and t his one



a

Det

woman

N

NP

in

P

a

Det

hat

N

NP

PPNP

with

P

a

Det

small

Adj

AdjP

child

N

N

NPPP

NP



This is an instance ofThis is an instance of

recursionrecursion::•• aa Noun PhraseNoun Phrase may contain amay contain a NounNoun

PhrasePhrase

•• ...which may contain another...which may contain another NounNounPhrasePhrase

•• ... which may contain another... which may contain another NounNoun

PhrasePhrase•• ... which may contain another... which may contain another NounNoun

PhrasePhrase



Another instance of recursionAnother instance of recursion

•• Kim arrived.Kim arrived.

•• Jo knew that Kim arrived.Jo knew that Kim arrived.

•• My mother knew that Jo knew that KimMy mother knew that Jo knew that Kim

arrived.arrived.

•• My sister told me that my mother knewMy sister told me that my mother knew

that Jo knew that Kim arrived.that Jo knew that Kim arrived.

•• My father heard that my sister told meMy father heard that my sister told me

that my mother knew that Jo knew thatthat my mother knew that Jo knew that

Kim arrived.Kim arrived.



What is recurring in this case?What is recurring in this case?

•• Last time it was NPs (and PPs)Last time it was NPs (and PPs)

•• What is it this time?What is it this time?




•• Kim arrivedKim arrived..

•• Jo knew thatJo knew that Kim arrivedKim arrived..


arrived.arrived.










•• Jo knew that Kim arrived.Jo knew that Kim arrived.


arrived.arrived.










•• Jo knew that Kim arrivedJo knew that Kim arrived..

•• My mother knew thatMy mother knew that Jo knew that KimJo knew that Kim

arrivedarrived..








Kim

NNP

arrived

VVP

S



KimN

NP

arrivedV

VP

S

JoN

NP

knewV S’

VP

S

thatComp S

S’



KimN

NP

arrivedV

VP

S

JoN

NP

knewV S’

VP

S

thatComp S

S’

S



Jo

NNP

knew

V

thatComp

Kim

N

NP

arrived

V

VPS

S’VP

S

S



Jo

NNP

knew

V

thatComp

Kim

N

NP

arrived

V

VPS

S’VP

S



And we can keep on going ...And we can keep on going ...



myDet

motherN

NP

knewV S’

VP

S

S



my

Det

mother

N

NP

knew

V

that

Comp

Jo

N

NP

knew

V

that

Comp

Kim

N

NP

arrived

V

VP

S

S’

VP

S

S’

VP

S



So: infinity out of finitenessSo: infinity out of finiteness

We need to remember onlyWe need to remember only

•• aa finite setfinite set of syntactic categoriesof syntactic categories

•• aa finite setfinite set of rules / tree fragmentsof rules / tree fragments

...and from that we can get an...and from that we can get an infiniteinfinite number of different sentences.number of different sentences.

S h d k bS h d k b



So what do we know aboutSo what do we know about

the syntax of our language?the syntax of our language?

How to make a sentence:How to make a sentence:

How to make an NP:How to make an NP:

How to make a VP:How to make a VP:

NP VP

S

Det N

NP

N

NP

V NP

VP

V

VP



Our theory of how speakersOur theory of how speakers

construct sentencesconstruct sentences•• Speakers know the syntactic categorySpeakers know the syntactic category

of each word in their lexicon:of each word in their lexicon:

– – know: Vknow: V – – man: Nman: N

– – big: Adjbig: Adj

•• Speakers know the syntactic rules ofSpeakers know the syntactic rules oftheir language, stated in terms of thesetheir language, stated in terms of thesecategories.categories.



But now we predict that theseBut now we predict that these

are all fine:are all fine:Jo ate the cake.Jo ate the cake.

Kim slept the child.Kim slept the child.

Jo devoured the cake.Jo devoured the cake.

Jo ate.Jo ate.

Jo devoured.Jo devoured.

Kim trusted her brother.Kim trusted her brother.

Kim relied her brotherKim relied her brother



... but of course they’re not... but of course they’re not

Jo ate the cake.Jo ate the cake.

** Kim slept the child.Kim slept the child.

Jo devoured the cake.Jo devoured the cake.

Jo ate.Jo ate.

** Jo devoured.Jo devoured.

Kim trusted her brother.Kim trusted her brother.

** Kim relied her brotherKim relied her brother



What went wrong?What went wrong?

•• We must learn more about a word thatWe must learn more about a word that

just just

– – its pronunciationits pronunciation

– – its meaningits meaning

– – its syntactic categoryits syntactic category

•• We must learn whatWe must learn what sisterssisters it can occurit can occur

with in the tree.with in the tree.

•• This is called itsThis is called its subcategorizationsubcategorization



For example...For example...

What do we know about “find”?What do we know about “find”?

The explorers found the North Pole.The explorers found the North Pole.The jurors found that he was innocent.The jurors found that he was innocent.

The explorers found.The explorers found.

The explorers found in the garden.The explorers found in the garden.



For example...For example...

What do we know about “find”?What do we know about “find”?

“find” can be followed by an NP“find” can be followed by an NP“find” can be followed by an S’“find” can be followed by an S’

2 ways to represent this2 ways to represent this




knowledge:knowledge:

find:find: V;V; ___ NP ___ NP

___ S’ ___ S’






find:find: V,V, ___ NP ___ NP

___ S’ ___ S’

“find” is a VVerb







___ S’ ___ S’

and it can have eit heran NP or an S’ as a sist er







___ S’ ___ S’

findfind

VV NPNP

VPVP

findfind

VV S’S’

VPVP

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