ling 388: language and computers sandiway fong lecture 24 11/15

LING 388: Language and Computers

Sandiway Fong

Lecture 24

11/15

Last Time

• Milestone: first machine translation…

Tree-to-tree mapping

• declarative example– John bought a book s(np(john),vp(v(bought),np(det(a),n(book)))) – Taroo-ga hon-o katta s(np(taroo),vp(np(hon),v(katta)))

• predicate maptree/2

Problems

Infinite loop

Subject Wh-questions

• subject wh-question– Who bought a book s(np(who),vp(v(bought),np(det(a),n(book))))– dare-ga hon-o katta ka s(np(dare),vp(np(hon),v(katta)))

• new word correspondences– dare = who– ka = question particle

• database facts– je(v(katta),v(bought)).– je(np(hon),np(_,n(book))).– je(np(taroo),np(john)).– je(np(dare),np(who)).

• does our translation code work for this case?

Object Wh-questions

• object wh-question– What did John buy sbar(np(what),aux(did),s(np(john),vp(v(buy))))– taroo-ga nani-o katta ka s(np(taroo),vp(np(nani),v(katta)))

• ka = question particle• ga = nominative case marker• o = accusative case marker

• new word correspondences– nani = what

• database facts– je(v(katta), v(bought)).– je(np(hon), np(_,n(book))).– je(np(taroo),np(john)).– je(np(dare), np(who)).

– je(np(nani), np(what)).

Object Wh-questions

• object wh-question– What did John buy sbar(np(what),aux(did),s(np(john),vp(v(buy))))– taroo-ga nani-o katta ka s(np(taroo),vp(np(nani),v(katta)))


– je(np(nani), np(what)). • can our translation code so far handle this case?

– i.e. can maptree/2 do the job?

Object Wh-questions• object wh-question

– What did John buy sbar(np(what),aux(did),s(np(john),vp(v(buy))))– taroo-ga nani-o katta ka s(np(taroo),vp(np(nani),v(katta)))


– je(np(nani), np(what)). – je(v(katta), v(buy)). % simplification

• can maptree/2 do the job?– maptree(s(S,vp(V,O)),s(SJ,vp(OJ,VJ))) :-

• je(SJ,S), • je(VJ,V), • je(OJ,O).

– maptree(sbar(O,_,s(S,vp(V))),s(SJ,vp(OJ,VJ))) :-• je(SJ,S), • je(VJ,V), • je(OJ,O).

Partial Summary

• That’s essentially the tree-to-tree mapping approach– (linguistic) construction-based

Next: • A more abstract approach

– mapping via predicate-argument structure

Mapping: Tree-to-tree• Tree-to-tree

– requires a complex maptree/2 definition– because of the different parse tree shapes

• Example 1 (Declarative case):– John bought a book s(np(john),vp(v(bought),np(det(a),n(book)))) – Taroo-ga hon-o katta s(np(taroo),vp(np(hon),v(katta)))

• Example 2 (Subject wh-Question):– Who bought a book s(np(who),vp(v(bought),np(det(a),n(book))))

– dare-ga hon-o katta ka s(np(dare),vp(np(hon),v(katta)))

• Example 3 (Object wh-Question):– What did John buy sbar(np(what),aux(did),s(np(john),vp(v(buy))))– taroo-ga nani-o katta ka s(np(taroo),vp(np(nani),v(katta)))

Mapping: Predicate-Argument Structure

• Predicate-argument– much more simple mapping– also the correspondence dictionary will be more simple too

• Example 1 (Declarative case):– John bought a book bought(john,book)

– Taroo-ga hon-o katta katta(taroo,hon)

• Example 2 (Subject wh-Question):– Who bought a book bought(who,book)

– dare-ga hon-o katta ka katta(dare,hon) • Example 3 (Object wh-Question):

– What did John buy bought(john,what)

– taroo-ga nani-o katta ka katta(taroo,nani)


• Task 1:– Modify the Japanese grammar to also generate predicate

argument structure• DCG rules

– 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].


• Task 1:– Modify the Japanese grammar to also generate predicate argument

structure• Modified DCG rules:

s(PA) --> np(Y,Q1), nomcase, vp(Z,Q2), sf(Q1,Q2), { predarg(Y,Z,PA) }.

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].


• Task 1:– Modify the Japanese grammar to also generate predicate argument

structure• predarg/3:

predarg(np(S),vp(np(O),v(V)),PA) :- PA =.. [V,S,O].• Examples:

?- js(PA,[taroo,ga,hon,o,katta],[]).

PA = katta(taroo,hon) ? ;

no

| ?- js(PA,[taroo,ga,nani,o,katta,ka],[]).

PA = katta(taroo,nani) ? ;

no

| ?- js(PA,[dare,ga,hon,o,katta,ka],[]).

PA = katta(dare,hon) ? ;

no


• Task 2:– Modify the English grammar to also generate predicate argument

structure• modified English DCG Rule

– s(PA) --> np(X), vp(Y), { predarg(X,Y,PA)}.• applies to

• John bought a book bought(john,book) • Who bought a book bought(who,book)

• predarg/3:predarg(SNP,vp(v(V),ONP),PA) :-

headof(SNP,S), headof(ONP,O), PA =.. [V,S,O].



structure• modified English DCG Rule

– s(PA) --> np(X), vp(Y), { predarg(X,Y,PA)}.• predarg/3:

predarg(SNP,vp(v(V),ONP),PA) :-headof(SNP,S), headof(ONP,O), PA =.. [V,S,O].

headof(np(S),S). % e.g. np(john) S= johnheadof(np(_Det,n(S)),S). % e.g. np(det(a),n(book)) S = book

• Examples:?- sbar(X,[john,bought,a,book],[]).X = bought(john,book) ? ;no| ?- sbar(X,[who,bought,a,book],[]).X = bought(who,book) ? ;no



structure• Example 3 (object wh-question)

– What did John buy bought(john,what)• modified English DCG Rule

sbar(PA) --> np(X,wh), do(_A), s_objectwh(Y), {predarg(X,Y,PA)}.

• predarg/3:predarg(ONP,s(SNP,vp(v(V))),PA) :-

headof(ONP,O), headof(SNP,S), PA =.. [V,S,O].• Example:

?- sbar(X,[what,did,john,buy],[]).X = buy(john,what) ? ;no

Translator: Predicate-Argument Mapping Version

translate(E,J) :-

var(E) -> translate2(E,J) ; translate1(E,J).

translate1(E,J) :-

sbar(X,E,[]), mapPA(X,Y), js(Y,J,[]).

translate2(E,J) :-

js(Y,J,[]), mapPA(X,Y), sbar(X,E,[]).

ling 388: language and computers sandiway fong lecture 24 11/15

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