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Xerox Research Centre Europe 26/11/1998 LFG-based syntactic transfer from English to French with XTE The Xerox Translation Environment.

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Presentation on theme: "Xerox Research Centre Europe 26/11/1998 LFG-based syntactic transfer from English to French with XTE The Xerox Translation Environment."— Presentation transcript:

1 Xerox Research Centre Europe 26/11/1998 LFG-based syntactic transfer from English to French with XTE The Xerox Translation Environment

2 Xerox Research Centre Europe 26/11/1998 The Translation Architecture Source and Target LFG Grammars Some Examples from the Corpus Transfer Coverage Rule Ordering in a Transfer Grammar Examples of “stepwise” Transfer: Nominalization and Coordination More on Coordination: Structure Deletion and Root Node Rewriting Translation Cycles and Optional Rules Overview

3 Xerox Research Centre Europe 26/11/1998 The Translation Architecture Source and Target LFG Grammars

4 Xerox Research Centre Europe 26/11/1998 The XTE Xerox Translation Environment Translation Architecture SL f-structure SL f-structure terms Source language string XLE parsing XTE term rewriting system Transfer rules TL f-structure terms underspecified TL f-structure Target language strings XLE generation disambiguation pred(f,walk) subj(f,g), pred(g,’John’) pred(A,walk) ==> pred(X,marcher). pred(A,’John’) ==> pred(X,’Jean’). pred(f,marcher), subj(f,g), pred(g,’Jean’)

5 Xerox Research Centre Europe 26/11/1998 The XTE Xerox Translation Environment Translation Architecture SL f-structure SL f-structure terms Source language string XLE parsing XTE term rewriting system Transfer rules TL f-structure terms underspecified TL f-structure Target language strings XLE generation disambiguation pred(f,walk) subj(f,g), pred(g,’John’) pred(A,walk) ==> pred(X,marcher). pred(A,’John’) ==> pred(X,’Jean’). pred(f,marcher), subj(f,g), pred(g,’Jean’) External Attributes addonly Internal Attributes

6 Xerox Research Centre Europe 26/11/1998 Source and Target Language LFG Grammars Source language grammar: English (Tracy Holloway King - PARC) Target language grammar: French (Anette Frank, Veronika Lux - XRCE) – Special focus on generation from underspecified structures – Use of ``optimality’’ (preference) marks and surface order constraints to define e.g. preferred default positions for adverbs of different types preferred default positions of adjuncts – LFG grammars are reversible, but specify different preference rankings for analysis and generation mode

7 Xerox Research Centre Europe 26/11/1998 Some Examples from the Corpus Transfer Coverage

8 Xerox Research Centre Europe 26/11/1998 To keep your HomeCentre in good operating condition, you need to perform periodic maintenance tasks. Pour assurer le bon fonctionnement du HomeCentre, vous devez effectuer périodiquement des tâches d’entretien. HEADER: Removing and Replacing the Paper Cassette HEADER: Retrait et mise en place de la cassette papier Before you add paper, make sure that the paper matches the paper size setting in Windows. Avant d’ajouter du papier, assurez-vous que le papier correspond au format de papier sélectionné. Keep in mind that you can’t use paper that is wider than 8 inches in the HomeCentre. N’oubliez pas que vous ne pouvez pas utiliser du papier qui dépasse 8 inches dans le HomeCentre. Fan the paper and put up to 125 sheets into the paper tray. Ventilez le papier et placez jusqu’à 125 feuilles dans le plateau de départ papier. Make sure that the green carriage lock lever is STILL moved all the way forward before you reinstall the print head. Assurez-vous que le levier vert de verrouillage du chariot est TOUJOURS repoussé complètement vers l’avant avant de remettre la tête d’impression en place. Some Examples from the Corpus

9 Xerox Research Centre Europe 26/11/1998 Transfer Coverage The transfer corpus: A contiguous section of the HomeCentre user manual -- Chapter 6 ( 99 sentences/text items) A basic transfer “grammar” for translation from English to French 545 compiled transfer rules: 171 structural transfer rules 76 lexicalized transfer rule templates (374 instantiated lexical transfer rules; approx. 5 entries per rule template) Translations for 94 sentences

10 Xerox Research Centre Europe 26/11/1998 Rule Ordering in a Transfer Grammar

11 Xerox Research Centre Europe 26/11/1998 Overall Organization of a Transfer Grammar Deleting grammar specific features of SL grammar Adjusting minor differences between SL and TL f-structures (e.g. create uniform feature space for nominals) General transformations on feature structures adjunct(A,B), in_set(C,B) ==> adjunct_x(A,C). Lexical and structural transfer rules nominalization verbs nouns adjectives adverbs conjunctions prepositions General transformations on feature structures ( ADJUNCT ) Final adjustments to match TL feature structures Input Output

12 Xerox Research Centre Europe 26/11/1998 % Simple verbs restriction/A :: 0 ==> 0. opt :: 0 ?=> 0. Source -> Target :: % main transfer rule pred(A,Source), +vtype(A,_) ==> pred(A, Target) && opt && restriction/A. open -> soulever. % optional opt :: 0 ==> 0. open -> ouvrir. % obligatory fan -> ventiler. restriction/A :: -obj(A,_) ==> inhrefl/A. print -> imprimer. % intransitive to intransitive reflexive appear -> afficher. Defining Optionality and Restrictions

13 Xerox Research Centre Europe 26/11/1998 Examples of “stepwise” Transfer: Nominalization

14 Xerox Research Centre Europe 26/11/1998 Nominalization HEADER: Removing the print head -- Retrait de la tête d’impression

15 Xerox Research Centre Europe 26/11/1998 Nominalization … when moving the printer --.. lors du déplacement de l’imprimante

16 Xerox Research Centre Europe 26/11/1998 nominal_or_verbal/A :: nominal_gerund_features/A, spectype(_)/A ==> spectype(def)/A ; verbal_gerund_features/A ==> spectype(def)/A, ntype(A,_), default_nominal_agr/A. nominalization(SourceVerb,TargetNoun) :: pred(A,SourceVerb), tns_features/A ?=> pred(A,TargetNoun), nominalized(A) && nominal_or_verbal/A. nominalization(print, impression). nominalization(move, déplacement). nominalization(remove, retrait). “Stepwise” Transfer Rewriting a verbal head with verbal features into a nominal head with nominal features First step: The nominalization rule

17 Xerox Research Centre Europe 26/11/1998 pred(0,remove) subj(0,1), pred(1,pro), pron_type(1,null) obj(0,2), pred(2,print head), ntype(2,2), grain(2,count), spec(2,4), spec_type(4,def), pers(2,’2’), num(2,sg), tns_asp(0,5), prog(5,+), perf(5,-), passive(0,-), pers(0,’2’), layout_type(0,header), stmt_type(0,header), vtype(0,main), num(0,sg), ntype(0,6), gerund(6,+), type(6,eventive). pred(A,remove), tns_asp(A,B), perf(B,_), prog(B,_), vtype(A,_), +ntype(A,C), gerund(C,+), type(C,eventive) ?=> pred(A,retrait), nominalized(A). Applying the nominalization rule to the input

18 Xerox Research Centre Europe 26/11/1998 pred(0,retrait), nominalized(0), subj(0,1), pred(1,pro), pron_type(1,null) obj(0,2), pred(2,print head), ntype(2,2), grain(2,count), spec(2,4), spec_type(4,def), pers(2,’2’), num(2,sg), passive(0,-), pers(0,’2’), layout_type(0,header), stmt_type(0,header), num(0,sg), ntype(0,6).

19 Xerox Research Centre Europe 26/11/1998 +nominalized(A), passive(A,-) subj(A,B), null_pron/B, obj(A,C) ==> adjunct_x(A,D), prepsem(de)/[D,C]. Second step: Relation changes in nominalization Case 1: active transitive verbs rewrite transitive object into de-adjunct; delete null subject Ex: start printing the page again ==> reprenez l’impression de la page

20 Xerox Research Centre Europe 26/11/1998 +nominalized(A), passive(A,-), subj(A,B), null_pron/B ==> 0. Second step: Relation changes in nominalization Case 2: active intransitive delete null subject Ex: start printing again ==> reprenez l’impression

21 Xerox Research Centre Europe 26/11/1998 +nominalized(A), passive(A,-), subj(A,B), null_pron/B ==> adjunct_x(A,C), prepsem(de)/[C,B]. Second step: Relation changes in nominalization Case 3: passive rewrite passive subject into de-adjunct Ex: when the scanner is being calibrated ==> pendant l’ étalonnage du scanner

22 Xerox Research Centre Europe 26/11/1998 pred(0,retrait), nominalized(0), spec(0,7), spec_type(7,def), subj(0,1), pred(1,pro), pron_type(1,null) obj(0,2), pred(2,print head), ntype(2,2), grain(2,count), spec(2,4), spec_type(4,def), pers(2,’2’), num(2,sg), passive(0,-), pers(0,’2’), layout_type(0,header), stmt_type(0,header), num(0,sg), ntype(0,6). +nominalized(A), passive(A,-) subj(A,B), null_pron/B, obj(A,C) ==> adjunct_x(A,D), prepsem(de)/[D,C]. Applying ``relation changes’’ to the (new) input

23 Xerox Research Centre Europe 26/11/1998 pred(0,retrait), nominalized(0), spec(0,7), spec_type(7,def), adjunct_x(0,8), pred(8,de), ptype(8,sem), obj(8,2), pcase(2,de), pred(2,print head), ntype(2,2), grain(2,count), spec(2,4), spec_type(4,def), pers(2,’2’), num(2,sg), pers(0,’2’), layout_type(0,header), stmt_type(0,header), num(0,sg), ntype(0,6). nominalized(A) ==> 0. pred(A,print head) ==> pred(A,tête d’impression). Retrait de la tête d’impression

24 Xerox Research Centre Europe 26/11/1998 You print a test page when you move the HomeCentre or replace an ink cartridge. Vous imprimez une page de test lorsque vous déplacez le HomeCentre ou (lors)que vous remplacez une cartouche d’encre. Another Example of “stepwise” Transfer: Head Switching in Coordination

25 Xerox Research Centre Europe 26/11/1998 You print a test page when you move the HomeCentre or replace an ink cartridge. Head Switching in Coordination pred(0,print), subj(0,1), pred(1,pro), pron_type(1,pers), pers(1,’2’), num(1,sg), obj(0,2), pred(2,test page), spec(2,3), spec_type(3,indef), pers(2,’3’), num(2,sg), tns_asp(0,4), tense(4,pres), perf(4,-), prog(4,-), passive(0,-), stmt_type(0,declarative), adjunct_x(0,5), pred(5,when), obj(5,6), conj_level(6,vp), conj_form(6,or), in_set(7,6), pred(7,move), subj(7,8), pred(8,pro), pron_type(8,pers), pers(8,’2’),num(8,sg), obj(7,9), pred(9,HomeCentre), ….. tns_asp(7,10), tense(10,pres), … passive(7,-), stmt_type(7,declarative) in_set(8,6), pred(8,replace), subj(8,9), pred(9,pro), pron_type(9,pers), pers(9,’2’),.. obj(8,10), pred(10,HomeCentre), ….. tns_asp(8,11), tense(11,pres), … passive(8,-), stmt_type(8,declarative). Source Structure:

26 Xerox Research Centre Europe 26/11/1998 Vous imprimez une page de test lorsque vous déplacez le HomeCentre ou (lors)que vous remplacez une cartouche d’encre. Head Switching in Coordination pred(0,imprimer), subj(0,1), pred(1,pro), pron_type(1,pers), pers(1,’2’), num(1,sg), obj(0,2), pred(2,page de test), spec(2,3), spec_type(3,indef), pers(2,’3’), num(2,sg), tns_asp(0,4), tense(4,pres), perf(4,-), passive(0,-), stmt_type(0,declarative), adjunct_x(0,6), conj_level(6,vp), conj_form(6,or), in_set(7,6), pred(7,lorsque), obj(7,8), pred(8,deplacer), subj(8,9), pred(9,pro), pron_type(9,pers), pers(9,’2’),... obj(8,10), pred(10,HomeCentre), ….. tns_asp(8,11), tense(11,pres), … passive(8,-), stmt_type(8,declarative) in_set(12,6), pred(12,lorsque), obj(12,13), pred(13,remplacer), subj(13,14), pred(14,pro), pron_type(14,pers),... obj(13,15), pred(15,HomeCentre), ….. tns_asp(13,16), tense(16,pres), … passive(13,-), stmt_type(13,declarative). Target Structure:

27 Xerox Research Centre Europe 26/11/1998 A simple way: Doing it in one step - rewrite the coordination structure, raise it to the level of the original conjunction (when) - rewrite the conjunction (when) twice as new conjuncts of new coordination structure, - let them embed the original conjuncts (B,C) Head Switching in Coordination semconj(CompForm,AdvType)/[A,Coord], coord(ConjForm)/[Coord,B,C] ==> coord(ConjForm)/[A,Bnew,Cnew], semconj(CompForm,AdvType)/[Bnew,B], semconj(CompForm,AdvType)/[Cnew,C].

28 Xerox Research Centre Europe 26/11/1998 A simple way: Doing it in one step - rewrite the coordination structure, raise it to the level of the original conjunction (when) - rewrite the conjunction (when) twice as new conjuncts of new coordination structure, - let them embed the original conjuncts (B,C) Head Switching in Coordination semconj(CompForm,AdvType)/[A,Coord], coord(ConjForm)/[Coord,B,C] ==> coord(ConjForm)/[A,Bnew,Cnew], semconj(CompForm,AdvType)/[Bnew,B], semconj(CompForm,AdvType)/[Cnew,C]. This rule only accounts for two-conjunct coordination !

29 Xerox Research Centre Europe 26/11/1998 “Stepwise” Transfer semconj(CompForm,AdvType)/[A,Coord], conj_form(Coord,ConjForm) ==> conj_form(A,ConjForm), raise_conjuncts_into_compl(CompForm,AdvType, Coord, A). +raise_conjuncts_into_compl(CompForm,AdvType, Coord, A), in_set(B,Coord), +subj(B,_) ==> in_set(Bnew,A), semconj(CompForm,AdvType)/[Bnew,B]. raise_conjuncts_into_compl(_,_,_,_) ==> 0. A better, more general way: Doing it in two steps - rewrite the coordination structure, raise it to the higher level (A) - delete the conjunction (when) - but transmit the conjunction form and the upper and lower nodes (Coord,A) to the next rule - the next rule creates, for each conjunct (B) of the raised coordination (Coord) a new conjunction (when) that embeds the original conjunct

30 Xerox Research Centre Europe 26/11/1998 More on Coordination: Structure Deletion and Root Node Rewriting

31 Xerox Research Centre Europe 26/11/1998 hold Press and release the green LED button. prolongée Exercez une pression brève sur le voyant vert. Structure Deletion and Root Node Rewriting

32 Xerox Research Centre Europe 26/11/1998 Structure Deletion and Root Node Rewriting

33 Xerox Research Centre Europe 26/11/1998 Press and hold the green LED button. Exercez une pression prolongée sur le voyant vert. v_coord_v(SourceV1, SourceV2, InterimV) :: conj_form(A,_), in_set(B,A), pred(B,SourceV1), in_set(C,A), pred(C,SourceV2), scopes(B,C) ==> pred(B,InterimV), rewrite(A,B), delete_structure(C). v_coord_v(press, hold, ’press-hold’). v_coord_v(press, hold, ’press-release’). First step: structure deletion rewrite(A,B), { A == var(0) } ==> move_structure(B, var(0)). rewrite(A,B), adjunct_x(X,A) ==> adjunct_x(X,B). Second step: (root) node rewriting

34 Xerox Research Centre Europe 26/11/1998 Press and hold the green LED button. Exercez une pression prolongée sur le voyant vert. v v_v_s_o2v_s_obl_o_adj(InterimV, TargetV, TargetSpecType, TargetNoun, TargetAdj, TargetPrep) :: pred(A,InterimV), x_arg/[obj,2,A,B] ==> pred(A,TargetV), x_arg/[obj,2,A,C], pred(C,TargetNoun), spectype(TargetSpecType)/C, ntype(C,_), default_nominal_agr/C, adjunct_x_adjective(TargetAdj)/C, x_arg/[obl,3,A,D], prepsem(TargetPrep)/[D,B]. v_v_s_o2v_s_obl_o_adj(‘press-hold’, exercer, indef, pression, prolongé, sur). v_v_s_o2v_s_obl_o_adj(‘press-release’, exercer, indef, pression, bref, sur). Third step: defining the target predicate and its arguments

35 Xerox Research Centre Europe 26/11/1998

36 Xerox Research Centre Europe 26/11/1998 Translation Cycles and Filtering Source and target language marking Filtering ``spurious’’ ambiguity paths from optional rules

37 Xerox Research Centre Europe 26/11/1998 Reinstall the print head -- Remettre la tête d’impression en place reinstall X ==> mettre X en place Keep it in a safe place -- Rangez-la en lieu sûr place ==> lieu * Remettre la tête d’impression en lieu Translation Cycles Source and Target Language Marking

38 Xerox Research Centre Europe 26/11/1998 Translation Cycles Source and Target Language Marking Introduce source language parameters pred(X,Pred) ==> pred(X,Pred,src). Rewriting source into target predicates pred(0,reinstall,src), +obj(0,_) ==> pred(0,remettre,trg), adjunct_x(0,1), pred(1,en,trg), arg(1,1,2), obj(1,2), ptype(1,sem), pcase(2,en), pred(2,place,trg), pers(2,’3’), num(2,sg), spec(2,3), spec_type(3,def). Eliminating target predicate marking pred(X,Pred,trg) ==> pred(X,Pred).

39 Xerox Research Centre Europe 26/11/1998 Reinstall the print head -- Remettre la tête d’impression en place reinstall X (src) ==> mettre X en place (trg) Keep it in a safe place -- Rangez-la en lieu sûr place (src) ==> lieu (trg) Remettre la tête d’impression en place Translation Cycles Source and Target Language Marking

40 Xerox Research Centre Europe 26/11/1998 pred(A,need,src) need ?=> il vous faut pred(A,need,src) pred(A,falloir,trg) need ?=> il est nécessaire de pred(A,need,src) pred(A, nécessaire,trg) need ==> devoir pred(A,devoir,trg) Ambiguity paths introduced by optional rules

41 Xerox Research Centre Europe 26/11/1998 need ==> devoir You need to perform periodic maintenance tasks. -- Vous devez effectuer périodiquement des tâches d’entretien. You do not need to perform maintenance tasks. -- * Vous ne devez pas effectuer des tâches d’entretien. -- Il n’est pas nécessaire d’effectuer des tâches d’entretien. restriction/A :: -adjunct_x(A,B) ==> 0; +adjunct_x(A,B), -adjunct_type(B,neg) ==> 0. SourceV ->TargetV :: pred(A,SourceV,src) ==> pred(A,TargetV,_), +vtype(A,_) && restriction/A. need -> devoir.

42 Xerox Research Centre Europe 26/11/1998 pred(A,need,src) need ?=> il vous faut pred(A,need,src) pred(A,falloir,trg) need ?=> il est nécessaire de pred(A,need,src) pred(A, nécessaire,trg) need ==> devoir pred(A,need,src) no application adjunct_type(_,neg) Ambiguity paths introduced by optional rules You do not need to perform maintenance tasks

43 Xerox Research Centre Europe 26/11/1998 pred(A,need,src) need ?=> il vous faut pred(A,need,src) pred(A,falloir,trg) need ?=> il est nécessaire de pred(A,need,src) pred(A, nécessaire,trg) need ==> devoir pred(A,need,src) Filtering ambiguity paths introduced by optional rules ``Stop’’ Predicate pred(_,_,src) ==> stop.


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