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))) 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)). 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))) 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)). –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)

Mapping: Predicate-Argument Structure 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].

Mapping: Predicate-Argument Structure 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].

Mapping: Predicate-Argument Structure 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

Mapping: Predicate-Argument Structure 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].

Mapping: Predicate-Argument Structure 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)}. 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= john headof(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

Mapping: Predicate-Argument Structure Task 2: –Modify the English grammar to also generate predicate argument 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,[]).