LING 388: Language and Computers

LING 388: Language and Computers Sandiway Fong Lecture 17: 10/25

Administrivia • Heads-up: • there may be a computer lab scheduled for next Wednesday • I’ll keep you posted ...

sbar np s[objectwh] aux what np did vp [objectwh] v john buy Last Time • English wh-questions • subject wh-questions: simple • object wh-questions: complex • wh-word fronting • do-support • tense goes with do • Technology employed • extra argument • nonterminal renaming

Today’s Topic • Components: • English Grammar • Japanese Grammar • Putting it all together... • Machine Translation (MT)

Japanese: Data • Declarative • Taroo-ga hon-o katta • John a book bought • ga = nominative case marker • o = accusative case marker • Wh-questions • Taroo-ga nani-o katta ka • nani: means what • ka: sentence-final question particle • dare-ga hon-o katta ka • dare: means who

Japanese: Grammar • 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]. can both parse and generate with this simple grammar

Japanese: Grammar • DCG rules: • js(s(Y,Z)) --> jnp(Y,Q1), nomcase, jvp(Z,Q2), sf(Q1,Q2). • jvp(vp(Z,Y),Q) --> jnp(Z,Q), acccase, jtransitive(Y). • jtransitive(v(katta)) --> [katta]. • nomcase --> [ga]. • acccase --> [o]. • jnp(np(taroo),notwh) --> [taroo]. • jnp(np(hon),notwh) --> [hon]. • jnp(np(dare),wh) --> [dare]. • jnp(np(nani),wh) --> [nani]. • sf(wh,notwh) --> [ka]. • sf(notwh,wh) --> [ka]. • sf(notwh,notwh) --> []. • sf(wh,wh) --> [ka]. rename Japanese nonterminals to not clash with English grammar – we’re going to be loading them both at the same time

English: Data • Declarative: • John bought a book • Wh-Questions: • Who bought a book? (subject wh-phrase) • *John bought what? (only possible as an echo-question) • What did John buy? (object wh-phrase)

DCG rules: sbar(sbar(X,A,Y)) --> np(X,wh), do(A), s_objectwh(Y). sbar(S) --> s(S). s_objectwh(s(Y,Z)) --> np(Y,_), vp_objectwh(Z). s(s(Y,Z)) --> np(Y,_), vp(Z). np(np(Y),Q) --> pronoun(Y,Q). np(np(Y),notwh) --> proper_noun(Y). np(np(D,N),Q) --> det(D,Number), common_noun(N,Number,Q). det(det(the),_) --> [the]. det(det(a),sg) --> [a]. common_noun(n(ball),sg,notwh) --> [ball]. common_noun(n(man),sg,notwh) --> [man]. common_noun(n(men),pl,notwh) --> [men]. common_noun(n(book),sg,notwh) --> [book]. pronoun(who,wh) --> [who]. pronoun(what,wh) --> [what]. pronoun(i,notwh) --> [i]. pronoun(we,notwh) --> [we]. pronoun(me,notwh) --> [me]. proper_noun(john) --> [john]. vp(vp(Y)) --> unergative(Y). vp(vp(Y,Z)) --> transitive(Y,_), np(Z,_). vp(vp(A,V)) --> aux(A), transitive(V,en). vp_objectwh(vp(Y)) --> transitive(Y,root). 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(did)) --> [did]. do(aux(does)) --> [does]. do(aux(do)) --> [do]. English: Grammar

English: Grammar • We can also generate with this grammar • like with the Japanese grammar • Examples: • ?- sbar(s(np(john),vp(v(bought),np(det(a),n(book)))),Y,[]). • Y = [john,bought,a,book] • ?- sbar(sbar(np(what),aux(did),s(np(john),vp(v(buy)))),Y,[]). • Y = [what,did,john,buy] • ?- sbar(s(np(who),vp(v(bought),np(det(a),n(book)))),Y,[]). • Y = [who,bought,a,book]

Example 1 • Declarative Example: • John bought a book • Taroo-ga hon-o katta • Word Correspondences: • katta = bought • hon = book • Taroo John • ga = nominative case marker • o = accusative case marker • Database facts: • je(katta,bought). • je(hon,book). • je(taroo,john).

Example 1 • Declarative Example: • John bought a book • Taroo-ga hon-o katta • Database facts: • je(katta,bought). • je(hon,book). • je(taroo,john). • Parse trees: • ?- sbar(X,[john,bought,a,book],[]). • X = s(np(john),vp(v(bought),np(det(a),n(book)))) • ?- js(X,[taroo,ga,hon,o,katta],[]). • X = s(np(taroo),vp(np(hon),v(katta))) • Translator (top-level): • ?- sbar(X,EnglishSentence,[]),maptree(X,Y),js(Y,JapaneseSentence,[]). • Problem reduces to: • How to write maptree/2 ?

Example 1 • 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))) • Database facts (modified): • je(katta,bought).je(v(katta),v(bought)). • je(hon,book). je(np(hon),np(_,n(book))). • % no corresponding indefinite determiner in Japanese • je(taroo,john).je(np(taroo),np(john)). • maptree/2: • Idea: • map subject to subject, verb to verb, object to object, and • respect word-order differences in the trees • maptree(s(S,vp(V,O)),s(SJ,vp(OJ,VJ))) :- • je(SJ,S), • je(VJ,V), • je(OJ,O).

Example 1 • 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))) • maptree/2: • maptree(s(S,vp(V,O)),s(SJ,vp(OJ,VJ))) :- • je(SJ,S), • je(VJ,V), • je(OJ,O). • je(v(katta),v(bought)). • je(np(hon),np(_,n(book))). • je(np(taroo),np(john)). • translate/2: • translate(E,J) :- • sbar(X,E,[]), • maptree(X,Xp), • js(Xp,J,[]). • Computation tree (modified): • ?- translate([john,bought,a,book],J). • ?- sbar(X,[john,bought,a,book,][]). • ?- maptree(X,Xp). • ?- js(Xp,J,[]).

Example 1 • 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))) • maptree/2: • maptree(s(S,vp(V,O)),s(SJ,vp(OJ,VJ))) :- • je(SJ,S), je(VJ,V), je(OJ,O). • je(v(katta),v(bought)). • je(np(hon),np(_,n(book))). • je(np(taroo),np(john)). • Computation tree (modified): • ?- translate([john,bought,a,book],J). • ?- sbar(X,[john,bought,a,book,][]). • X =s(np(john),vp(v(bought),np(det(a),n(book)))) • ?- maptree(s(np(john),vp(v(bought),np(det(a),n(book)))),Xp). • ?- js(Xp,J,[]). • ?- maptree(s(np(john),vp(v(bought),np(det(a),n(book)))),Xp). • S = np(john) V = v(bought) O = np(det(a),n(book)) Xp = s(SJ,vp(OJ,VJ) • ?- je(SJ,np(john)). • SJ = np(taroo) • ?- je(VJ,v(bought)). • VJ = v(katta) • ?- je(OJ,np(det(a),n(book))). • OJ = np(hon) • ?- js(s(np(taroo),vp(np(hon),v(katta))),J,[]). • J = [taroo,ga,hon,o,katta]

Example 1 • 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))) • Query (EJ): • ?- translate([john,bought,a,book],J). • J = [taroo,ga,hon,o,katta] • Query (JE): • ?- translate(E,[taroo,ga,hon,o,katta]). • E = [john,bought,the,book] (surprising!) • Computation tree (JE): • ?- translate(E,[taroo,ga,hon,o,katta]). • ?- sbar(X,E,[]). • ?- maptree(X,Xp). • ?- js(Xp,[taroo,ga,hon,o,katta],[]). • What does the query ?- sbar(X,E,[]). do? • X represents the parse tree • E represents the input sentence • but both arguments are variables! • i.e. we’re not providing any information to the English grammar/parser • translate(E,J) :- • sbar(X,E,[]), • maptree(X,Xp), • js(Xp,J,[]).

Example 1 ?- sbar(X,E,[]). E = [who,did,who,hit], X = sbar(np(who),aux(did),s(np(who),vp(v(hit)))) ? ; E = [who,did,who,eat], X = sbar(np(who),aux(did),s(np(who),vp(v(eat)))) ? ; E = [who,did,who,buy], X = sbar(np(who),aux(did),s(np(who),vp(v(buy)))) ? ; E = [who,did,what,hit], X = sbar(np(who),aux(did),s(np(what),vp(v(hit)))) ? ; E = [who,did,what,eat], X = sbar(np(who),aux(did),s(np(what),vp(v(eat)))) ? ; E = [who,did,what,buy], X = sbar(np(who),aux(did),s(np(what),vp(v(buy)))) ? ; E = [who,did,i,hit], X = sbar(np(who),aux(did),s(np(i),vp(v(hit)))) ? ; E = [who,did,i,eat], X = sbar(np(who),aux(did),s(np(i),vp(v(eat)))) ? ; E = [who,did,i,buy], X = sbar(np(who),aux(did),s(np(i),vp(v(buy)))) ? ; E = [who,did,we,hit], X = sbar(np(who),aux(did),s(np(we),vp(v(hit)))) ? ; E = [who,did,we,eat], X = sbar(np(who),aux(did),s(np(we),vp(v(eat)))) ? ; E = [who,did,we,buy], X = sbar(np(who),aux(did),s(np(we),vp(v(buy)))) ? ; E = [who,did,me,hit], X = sbar(np(who),aux(did),s(np(me),vp(v(hit)))) ? ; E = [who,did,me,eat], X = sbar(np(who),aux(did),s(np(me),vp(v(eat)))) ? ; E = [who,did,me,buy], X = sbar(np(who),aux(did),s(np(me),vp(v(buy)))) ? ; E = [who,did,john,hit], X = sbar(np(who),aux(did),s(np(john),vp(v(hit)))) ? ; E = [who,did,john,eat], X = sbar(np(who),aux(did),s(np(john),vp(v(eat)))) ? ; E = [who,did,john,buy], X = sbar(np(who),aux(did),s(np(john),vp(v(buy)))) ? ; E = [who,did,the,ball,hit], X = sbar(np(who),aux(did),s(np(det(the),n(ball)),vp(v(hit)))) ? ; • What does the query ?- sbar(X,E,[]). do? • X represents the parse tree • Y represents the input sentence • but both arguments are variables! • The English grammar doesn’t just parse and generate • but it is also an enumerater

Example 1 ?- findall((X,Y),sbar(X,Y,[]),L),length(L,N). L = [(sbar(np(who),aux(did),s(np(who),vp(v(hit)))),[who,did,who,hit]),(sbar(np(who),aux(did),s(np(who),vp(v(eat)))),[who,did,who,eat]),(sbar(np(who),aux(did),s(np(who),vp(v(buy)))),[who,did,who,buy]),(sbar(np(who),aux(did),s(np(what),vp(v(hit)))),[who,did,what,hit]),(sbar(np(who),aux(did),s(np(what),vp(v(eat)))),[w\ ho,did,what,eat]),(sbar(np(who),aux(did),s(np(what),vp(v(...)))),[who,did,what,buy]),(sbar(np(who),aux(did),s(np(...),vp(...))),[who,did,i|...]),(sbar(np(...),aux(...),s(...)),[who,did|...]),(sbar(...),[...|...]),(...,...)|...], N = 1456 ? yes • What does the query ?- sbar(X,E,[]). do? • X represents the parse tree • Y represents the input sentence • but both arguments are variables! • The English grammar doesn’t just parse and generate • but it is also an enumerater

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))) • 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? • Yes! • In maptree/2, we pattern-match: • s(np(who),vp(v(bought),np(det(a),n(book)))) • s(S,vp(V,O)) • S = np(who) V = v(bought) O = np(det(a),n(book)) • output: • SJ = np(dare) VJ= v(katta) OJ = np(hon) • s(SJ,vp(OJ,VJ)) • s(np(dare),vp(np(hon),v(katta))) • translate(E,J) :- • sbar(X,E,[]), • maptree(X,Xp), • js(Xp,J,[]). • maptree(s(S,vp(V,O)),s(SJ,vp(OJ,VJ))) :- • je(SJ,S), • je(VJ,V), • je(OJ,O).

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))) • 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? Yes! • Queries: • ?- translate([who,bought,a,book],J). • J = [dare,ga,hon,o,katta,ka] • ?- translate(E,[dare,ga,hon,o,katta,ka]). • E = [who,bought,the,book] • Why “the” and not “a” is generated ? • translate(E,J) :- • sbar(X,E,[]), • maptree(X,Xp), • js(Xp,J,[]). • maptree(s(S,vp(V,O)),s(SJ,vp(OJ,VJ))) :- • je(SJ,S), • je(VJ,V), • je(OJ,O). • Mapping result: • s(np(who),vp(v(bought),np(_,n(book)))) • np(np(D,N),Q) --> det(D,Number), common_noun(N,Number,Q). • det(det(the),_) --> [the]. • det(det(a),sg) --> [a].

Next Time • We’ll look at the object wh-question case ... • 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)))

LING 388: Language and Computers