LING 388: Language and Computers

Sandiway Fong

Lecture 24: 11/16

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Last Time

• Japanese language properties– head-final: Subject Object Verb– case particles: -ga (nominative), -o (accusative)– wh-in-situ (not fronted): dare (who), nani (what)– sentence-final Q-particle: ka

• examples– Taroo-ga hon-o katta (declarative)– taroo-nom book-acc bought– Taroo-ga nani-o katta ka (object wh-question)– dare-ga hon-o katta ka (subject wh-question)

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Last Time

• DCG grammar for Japanese– s(s(Y,Z)) --> np(Y,Q1), nomcase, vp(Z,Q2), sf(Q1,Q2).– vp(vp(Z,Y),Q) --> np(Z,Q), acccase, transitive(Y).– transitive(v(katta)) --> [katta].

– nomcase --> [ga].– acccase --> [o].

– np(np(taroo),notwh) --> [taroo].– np(np(hon),notwh) --> [hon].– np(np(dare),wh) --> [dare].– np(np(nani),wh) --> [nani].

– sf(wh,notwh) --> [ka].– sf(notwh,wh) --> [ka].– sf(notwh,notwh) --> [].– sf(wh,wh) --> [ka].

we can both parse and generatewith thissimple grammar

NPs have an extra argument{notwh,wh}nomcase, acccase and sf are new nonterminals thatdon’t generate any structure

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Exercise 1

• Test the Japanese grammar

• Sentences:– Taroo-ga hon-o katta

John-nom book-acc buy-PAST

– dare-ga hon-o katta ka

who-nom book-acc buy-PAST Q

– *dare-ga hon-o katta

who-nom book-acc buy-PAST

– Taroo-ga nani-o katta ka

John-nom what-acc buy-PAST Q

– *Taroo-ga nani-o katta

John-nom what-acc buy-PAST

– dare-ga nani-o katta ka

who-nom what-acc buy-PAST Q

– *dare-ga nani-o katta

who-nom what-acc buy-PAST

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Wh-Questions: English

• English– declarative

• John bought a book

– wh-question• Who bought a book? (subject wh-phrase)• *John bought what? (only possible as an echo-question)• What did John buy? (object wh-phrase)

• grammar implementation– subject wh-question

• straightforward - same word order as declarative counterpart

– object wh-question• complex operation (irregular)

– object wh-phrase must be fronted– do-support (insertion of past tense form of “do”)– bought buy (untensed form)

John bought a bookJohn bought whatwhat John boughtwhat did John boughtwhat did John buy

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English Grammar

• starting points(s(Y,Z)) --> np(Y), vp(Z). np(np(Y)) --> pronoun(Y).np(np(D,N)) --> det(D,Number),

common_noun(N,Number).det(det(the),_) --> [the].det(det(a),sg) --> [a].common_noun(n(ball),sg) --> [ball].common_noun(n(man),sg) --> [man].common_noun(n(men),pl) --> [men].pronoun(i) --> [i].pronoun(we) --> [we].pronoun(me) --> [me]. vp(vp(Y)) --> unergative(Y). vp(vp(Y,Z)) --> transitive(Y,_), np(Z).vp(vp(A,V)) --> aux(A), transitive(V,en).unergative(v(ran)) --> [ran].transitive(v(hit),_) --> [hit].transitive(v(eat),root) --> [eat].transitive(v(eats),s) --> [eats].transitive(v(ate),ed) --> [ate].transitive(v(eaten),en) --> [eaten].aux(aux(was)) --> [was].

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Exercise 2: Step 1

• Let’s modify the example grammar to handle the following sentences

• declarative– John bought a book

• wh-question– Who bought a book?– (subject wh-phrase)– *John bought what?– (only possible as an echo-question)– What did John buy?– (object wh-phrase)

• add rules for the new words– bought book john

– who what

• Note: the Japanese grammar incorporates the wh/notwh feature– np(np(taroo),notwh) -->

[taroo].– np(np(hon),notwh) --> [hon].– np(np(dare),wh) --> [dare].– np(np(nani),wh) --> [nani].

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Exercise 2: Step 1

• wh-feature has been added to nouns– got to pass wh feature information up to the noun phrase node level

• grammar rules– s(s(Y,Z)) --> np(Y,Q), vp(Z). – np(np(Y),Q) --> pronoun(Y,Q).– np(np(N),notwh) --> proper_noun(N).– np(np(D,N),Q) --> det(D,Number),common_noun(N,Number,Q).– vp(vp(Y,Z)) --> transitive(Y,_), np(Z,Q).

• Check your grammar• declarative sentences should work as before

– ?- s(X,[john,bought,a,book],[]).– X = s(np(john),vp(v(bought),np(det(a),n(book))))

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Exercise 2: Step 1

• check the grammar• subject wh-question

– ?- s(X,[who,bought,a,book],[]).– X = s(np(who),vp(v(bought),np(det(a),n(book))))

• note– this is an overly simple in-situ analysis– (normally, it is assumed that who is raised to a higher specifier position, e.g. Specifier

of CP)

• object wh-question– ?- s(X,[john,bought,what],[]).– X = s(np(john),vp(v(bought),np(what)))

• assuming it’s not an echo question• how do we block this analysis?

– by stipulating the value of Q to be notwh– vp(vp(Y,Z)) --> transitive(Y,_), np(Z,notwh).

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Exercise 2: Step 2

• grammar– s(s(Y,Z)) --> np(Y,Q), vp(Z). – vp(vp(Y,Z)) --> transitive(Y,_),

np(Z,notwh).– pronoun(who,wh) --> [who].– pronoun(what,wh) --> [what].

• object wh-question– ?- s(X,[what,did,john,buy],[]).

• we need to write rules for wh-object fronting– First, some rules for “do”– aux(aux(was)) --> [was].

– do(aux(did)) --> [did].– do(aux(do)) --> [do].– do(aux(does)) --> [does].

s

np vp

v

sbar

np

what

buy

john

aux

did

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Exercise 2: Step 2• grammar

– s(s(Y,Z)) --> np(Y,Q), vp(Z). – vp(vp(Y,Z)) --> transitive(Y,_), np(Z,notwh).– pronoun(who,wh) --> [who].– pronoun(what,wh) --> [what].

• object wh-question– complex operation (irregular)

– object wh-phrase must be fronted– do-support (insertion of past tense form of “do”)– bought buy (untensed form)

– fronting– sbar(sbar(X,Y)) --> np(X,wh), s(Y).

s

np vp

v

sbar

np

what

buy

john

aux

did

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Exercise 2: Step 2

• grammar– s(s(Y,Z)) --> np(Y,Q), vp(Z). – vp(vp(Y,Z)) --> transitive(Y,_), np(Z,notwh).– pronoun(who,wh) --> [who].– pronoun(what,wh) --> [what].

• object wh-question– complex operation (irregular)

– object wh-phrase must be fronted

– do-support (insertion of past tense form of “do”)

– bought buy (untensed form)

– do-support– sbar(sbar(X,A,Y)) --> np(X,wh), do(A), s(Y).

s

np vp

v

sbar

np

what

buy

john

aux

did

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Exercise 2: Step 3

• grammar – sbar(sbar(X,A,Y)) --> np(X,wh), do(A), s(Y).– s(s(Y,Z)) --> np(Y,Q), vp(Z). – vp(vp(Y,Z)) --> transitive(Y,_),

np(Z,notwh).– pronoun(who,wh) --> [who].– pronoun(what,wh) --> [what].

• object wh-question

– complex operation (irregular)– object wh-phrase must be fronted– do-support (insertion of past tense form of “do”)– bought buy (untensed form)

– untensed main verb– transitive(v(bought),ed) --> [bought].– transitive(v(buy),root) --> [buy].

s

np vp

v

sbar

np

what

buy

john

aux

did

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Exercise 2: Step 3

• grammar– sbar(sbar(X,A,Y)) --> np(X,wh), do(A), s(Y).– s(s(Y,Z)) --> np(Y,Q), vp(Z). – vp(vp(Y,Z)) --> transitive(Y,_), np(Z,notwh).– pronoun(who,wh) --> [who].– pronoun(what,wh) --> [what].

• Object wh-question:– complex operation (irregular)

– object wh-phrase must be fronted– do-support (insertion of past tense form of “do”)– bought buy (untensed form)

– VP rule for missing (fronted) object– transitive(v(buy),root) --> [buy].1. vp(vp(Y)) --> transitive(Y,root).

s

np vp

v

sbar

np

what

buy

john

aux

did

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Exercise 2: Step 3

• Grammar check

• Test the modified grammar on– What did John buy?

• Does the grammar accept– John bought what?

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Exercise 2: Step 4

• How do we force our VP fronted rule to be used?

• One method: – signal or pass information down the

tree encoded in the nonterminal name

• Modify rule– sbar(sbar(X,A,Y)) -->

np(X,wh), do(A), s_objectwh(Y).

• Add new rule– s_objectwh(s(Y,Z)) -->

np(Y,Q), vp_objectwh(Z). • Modify rule

– vp_objectwh(vp(Y)) --> transitive(Y,root).

s[objectwh]

np vp [objectwh]

v

sbar

np

what

buy

john

aux

did

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Exercise 2: Step 4

• Check all the original sentences work– Declarative:

• John bought a book

– Wh-Question:• Who bought a book? (subject wh-phrase)• *John bought what? (only possible as an echo-

question)• What did John buy? (object wh-phrase)

• grammar – s(s(Y,Z)) --> np(Y,Q), vp(Z). – vp(vp(Y,Z)) --> transitive(Y,_), np(Z,notwh).– pronoun(who,wh) --> [who].– pronoun(what,wh) --> [what].– sbar(sbar(X,A,Y)) --> np(X,wh), do(A),

s_objectwh(Y).– s_objectwh(s(Y,Z)) --> np(Y,Q), vp_objectwh(Z). – vp_objectwh(vp(Y)) --> transitive(Y,root).

• query– ?- sbar(X,[what,did,john,buy],[]).– X = sbar(np(what),aux(did),s(np(john),vp(v(buy))))

• cleaning up, add new rule– sbar(S) --> s(S).

s[objectwh]

np vp [objectwh]

v

sbar

np

what

buy

john

aux

did

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Exercise 3

• Subject and object wh-nouns do not end up in the same place in this simple grammar.

• Modify the grammar to use traces of movement.

• Generate the following structures:– [Sbar Who [S [NP trace] [VP bought [NP a book]]]]– [Sbar What did [S [NP John] [VP buy [NP trace]]]]

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Exercise 3• sbar(sbar(X,Y,Z)) --> np(X,wh), do(Y), s_objectwh(Z).• sbar(sbar(X,Y)) --> np(X,wh), s_subjectwh(Y).• sbar(S) --> s(S). % convenience• s(s(Y,Z)) --> np(Y,notwh), vp(Z).• s_subjectwh(s(np(trace),Z)) -->

np(np(trace),WH), vp(Z).• s_objectwh(s(Y,Z)) --> np(Y,WH), vp_objectwh(Z).• np(np(trace),_) --> [].• np(np(X),notwh) --> propernoun(X).• np(np(Y),WH) --> pronoun(Y,WH).• np(np(D,N),notwh) --> det(D,Number),

common_noun(N,Number).• det(det(the),_) --> [the].• det(det(a),sg) --> [a].• propernoun(john) --> [john].• common_noun(n(ball),sg) --> [ball].• common_noun(n(man),sg) --> [man].• common_noun(n(men),pl) --> [men].• common_noun(n(book),sg) --> [book].

• pronoun(i,notwh) --> [i].• pronoun(we,notwh) --> [we].• pronoun(me,notwh) --> [me].• pronoun(who,wh) --> [who].• pronoun(what,wh) --> [what].• vp(vp(Y)) --> unergative(Y).• vp(vp(Y,Z)) --> transitive(Y,_), np(Z,notwh).• vp_objectwh(vp(Y,np(trace))) --> transitive(Y,root),

np(np(trace),_).• vp(vp(A,V)) --> aux(A), transitive(V,en).• unergative(v(ran)) --> [ran].• transitive(v(hit),_) --> [hit].• transitive(v(eat),root) --> [eat].• transitive(v(eats),s) --> [eats].• transitive(v(ate),ed) --> [ate].• transitive(v(eaten),en) --> [eaten].• transitive(v(buy),root) --> [buy].• transitive(v(bought),ed) --> [bought].• aux(aux(was)) --> [was].• do(aux(was)) --> [did].

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Next Time

• We’ll talk about machine translation