Nov 17, 2005Learning-based MT1 Learning-based MT Approaches for Languages with Limited Resources Alon Lavie Language Technologies Institute Carnegie Mellon University Joint work with: Jaime Carbonell, Lori Levin, Kathrin Probst, Erik Peterson, Christian Monson, Ariadna Font-Llitjos, Alison Alvarez, Roberto Aranovich

Nov 17, 2005Learning-based MT2 Outline Rationale for learning-based MT Roadmap for learning-based MT Framework overview Elicitation Learning transfer Rules Automatic rule refinement Learning Morphology Example prototypes Implications for MT with vast parallel data Conclusions and future directions

Nov 17, 2005Learning-based MT3 Machine Translation: Where are we today? Age of Internet and Globalization – great demand for MT: –Multiple official languages of UN, EU, Canada, etc. –Documentation dissemination for large manufacturers (Microsoft, IBM, Caterpillar) Economic incentive is still primarily within a small number of language pairs Some fairly good commercial products in the market for these language pairs –Primarily a product of rule-based systems after many years of development Pervasive MT between most language pairs still non- existent and not on the immediate horizon

Nov 17, 2005Learning-based MT4 Mi chiamo Alon LavieMy name is Alon Lavie Give-information+personal-data (name=alon_lavie) [ s [ vp accusative_pronoun “chiamare” proper_name]] [ s [ np [possessive_pronoun “name”]] [ vp “be” proper_name]] Direct Transfer Interlingua Analysis Generation Approaches to MT: Vaquois MT Triangle

Nov 17, 2005Learning-based MT5 Progression of MT Started with rule-based systems –Very large expert human effort to construct language- specific resources (grammars, lexicons) –High-quality MT extremely expensive  only for handful of language pairs Along came EBMT and then SMT… –Replaced human effort with extremely large volumes of parallel text data –Less expensive, but still only feasible for a small number of language pairs –We “traded” human labor with data Where does this take us in 5-10 years? –Large parallel corpora for maybe language pairs What about all the other languages? Is all this data (with very shallow representation of language structure) really necessary? Can we build MT approaches that learn deeper levels of language structure and how they map from one language to another?

Nov 17, 2005Learning-based MT6 Why Machine Translation for Languages with Limited Resources? We are in the age of information explosion –The internet+web+Google  anyone can get the information they want anytime… But what about the text in all those other languages? –How do they read all this English stuff? –How do we read all the stuff that they put online? MT for these languages would Enable: –Better government access to native indigenous and minority communities –Better minority and native community participation in information-rich activities (health care, education, government) without giving up their languages. –Civilian and military applications (disaster relief) –Language preservation

Nov 17, 2005Learning-based MT7 The Roadmap to Learning-based MT Automatic acquisition of necessary language resources and knowledge using machine learning methodologies: –Learning morphology (analysis/generation) –Rapid acquisition of broad coverage word-to-word and phrase-to-phrase translation lexicons –Learning of syntactic structural mappings Tree-to-tree structure transformations [Knight et al], [Eisner], [Melamed] require parse trees for both languages Learning syntactic transfer rules with resources (grammar, parses) for just one of the two languages –Automatic rule refinement and/or post-editing A framework for integrating the acquired MT resources into effective MT prototype systems Effective integration of acquired knowledge with statistical/distributional information

Nov 17, 2005Learning-based MT8 CMU’s AVENUE Approach Elicitation: use bilingual native informants to produce a small high-quality word-aligned bilingual corpus of translated phrases and sentences –Building Elicitation corpora from feature structures –Feature Detection and Navigation Transfer-rule Learning: apply ML-based methods to automatically acquire syntactic transfer rules for translation between the two languages –Learn from major language to minor language –Translate from minor language to major language XFER + Decoder: –XFER engine produces a lattice of possible transferred structures at all levels –Decoder searches and selects the best scoring combination Rule Refinement: refine the acquired rules via a process of interaction with bilingual informants Morphology Learning Word and Phrase bilingual lexicon acquisition

Nov 17, 2005Learning-based MT9 AVENUE MT Approach Interlingua Syntactic Parsing Semantic Analysis Sentence Planning Text Generation Source (e.g. Quechua) Target (e.g. English) Transfer Rules Direct: SMT, EBMT AVENUE: Automate Rule Learning

Nov 17, 2005Learning-based MT10 AVENUE Architecture Learning Module Transfer Rules {PP,4894} ;;Score: PP::PP [NP POSTP] -> [PREP NP] ((X2::Y1) (X1::Y2)) Translation Lexicon Run Time Transfer System Lattice Decoder English Language Model Word-to-Word Translation Probabilities Word-aligned elicited data

Nov 17, 2005Learning-based MT11 Outline Rationale for learning-based MT Roadmap for learning-based MT Framework overview Elicitation Learning transfer Rules Automatic rule refinement Learning Morphology Example prototypes Implications for MT with vast parallel data Conclusions and future directions

Nov 17, 2005Learning-based MT12 Data Elicitation for Languages with Limited Resources Rationale: –Large volumes of parallel text not available  create a small maximally-diverse parallel corpus that directly supports the learning task –Bilingual native informant(s) can translate and align a small pre-designed elicitation corpus, using elicitation tool –Elicitation corpus designed to be typologically and structurally comprehensive and compositional –Transfer-rule engine and new learning approach support acquisition of generalized transfer-rules from the data

Nov 17, 2005Learning-based MT13 Elicitation Tool: English-Chinese Example

Nov 17, 2005Learning-based MT14 Elicitation Tool: English-Chinese Example

Nov 17, 2005Learning-based MT15 Elicitation Tool: English-Hindi Example

Nov 17, 2005Learning-based MT16 Elicitation Tool: English-Arabic Example

Nov 17, 2005Learning-based MT17 Elicitation Tool: Spanish-Mapudungun Example

Nov 17, 2005Learning-based MT18 Designing Elicitation Corpora What do we want to elicit? –Diversity of linguistic phenomena and constructions –Syntactic structural diversity How do we construct an elicitation corpus? –Typological Elicitation Corpus based on elicitation and documentation work of field linguists (e.g. Comrie 1977, Bouquiaux 1992): initial corpus size ~1000 examples –Structural Elicitation Corpus based on representative sample of English phrase structures: ~120 examples Organized compositionally: elicit simple structures first, then use them as building blocks Goal: minimize size, maximize linguistic coverage

Nov 17, 2005Learning-based MT19 Typological Elicitation Corpus Feature Detection –Discover what features exist in the language and where/how they are marked Example: does the language mark gender of nouns? How and where are these marked? –Method: compare translations of minimal pairs – sentences that differ in only ONE feature Elicit translations/alignments for detected features and their combinations Dynamic corpus navigation based on feature detection: no need to elicit for combinations involving non-existent features

Nov 17, 2005Learning-based MT20 Typological Elicitation Corpus Initial typological corpus of about 1000 sentences was manually constructed New construction methodology for building an elicitation corpus using: –A feature specification: lists inventory of available features and their values –A definition of the set of desired feature structures Schemas define sets of desired combinations of features and values Multiplier algorithm generates the comprehensive set of feature structures –A generation grammar and lexicon: NLG generator generates NL sentences from the feature structures

Nov 17, 2005Learning-based MT21 Structural Elicitation Corpus Goal: create a compact diverse sample corpus of syntactic phrase structures in English in order to elicit how these map into the elicited language Methodology: –Extracted all CFG “rules” from Brown section of Penn TreeBank (122K sentences) –Simplified POS tag set –Constructed frequency histogram of extracted rules –Pulled out simplest phrases for most frequent rules for NPs, PPs, ADJPs, ADVPs, SBARs and Sentences –Some manual inspection and refinement Resulting corpus of about 120 phrases/sentences representing common structures See [Probst and Lavie, 2004]

Nov 17, 2005Learning-based MT22 Outline Rationale for learning-based MT Roadmap for learning-based MT Framework overview Elicitation Learning transfer Rules Automatic rule refinement Learning Morphology Example prototypes Implications for MT with vast parallel data Conclusions and future directions

Nov 17, 2005Learning-based MT23 Transfer Rule Formalism Type information Part-of-speech/constituent information Alignments x-side constraints y-side constraints xy-constraints, e.g. ((Y1 AGR) = (X1 AGR)) ; SL: the old man, TL: ha-ish ha-zaqen NP::NP [DET ADJ N] -> [DET N DET ADJ] ( (X1::Y1) (X1::Y3) (X2::Y4) (X3::Y2) ((X1 AGR) = *3-SING) ((X1 DEF = *DEF) ((X3 AGR) = *3-SING) ((X3 COUNT) = +) ((Y1 DEF) = *DEF) ((Y3 DEF) = *DEF) ((Y2 AGR) = *3-SING) ((Y2 GENDER) = (Y4 GENDER)) )

Nov 17, 2005Learning-based MT24 Transfer Rule Formalism (II) Value constraints Agreement constraints ;SL: the old man, TL: ha-ish ha-zaqen NP::NP [DET ADJ N] -> [DET N DET ADJ] ( (X1::Y1) (X1::Y3) (X2::Y4) (X3::Y2) ((X1 AGR) = *3-SING) ((X1 DEF = *DEF) ((X3 AGR) = *3-SING) ((X3 COUNT) = +) ((Y1 DEF) = *DEF) ((Y3 DEF) = *DEF) ((Y2 AGR) = *3-SING) ((Y2 GENDER) = (Y4 GENDER)) )

Nov 17, 2005Learning-based MT25 Rule Learning - Overview Goal: Acquire Syntactic Transfer Rules Use available knowledge from the source side (grammatical structure) Three steps: 1.Flat Seed Generation: first guesses at transfer rules; flat syntactic structure 2.Compositionality Learning: use previously learned rules to learn hierarchical structure 3.Constraint Learning: refine rules by learning appropriate feature constraints

Nov 17, 2005Learning-based MT26 Flat Seed Rule Generation Learning Example: NP Eng: the big apple Heb: ha-tapuax ha-gadol Generated Seed Rule: NP::NP [ART ADJ N]  [ART N ART ADJ] ((X1::Y1) (X1::Y3) (X2::Y4) (X3::Y2))

Nov 17, 2005Learning-based MT27 Flat Seed Rule Generation Create a “flat” transfer rule specific to the sentence pair, partially abstracted to POS –Words that are aligned word-to-word and have the same POS in both languages are generalized to their POS –Words that have complex alignments (or not the same POS) remain lexicalized One seed rule for each translation example No feature constraints associated with seed rules (but mark the example(s) from which it was learned)

Nov 17, 2005Learning-based MT28 Compositionality Learning Initial Flat Rules: S::S [ART ADJ N V ART N]  [ART N ART ADJ V P ART N] ((X1::Y1) (X1::Y3) (X2::Y4) (X3::Y2) (X4::Y5) (X5::Y7) (X6::Y8)) NP::NP [ART ADJ N]  [ART N ART ADJ] ((X1::Y1) (X1::Y3) (X2::Y4) (X3::Y2)) NP::NP [ART N]  [ART N] ((X1::Y1) (X2::Y2)) Generated Compositional Rule: S::S [NP V NP]  [NP V P NP] ((X1::Y1) (X2::Y2) (X3::Y4))

Nov 17, 2005Learning-based MT29 Compositionality Learning Detection: traverse the c-structure of the English sentence, add compositional structure for translatable chunks Generalization: adjust constituent sequences and alignments Two implemented variants: –Safe Compositionality: there exists a transfer rule that correctly translates the sub-constituent –Maximal Compositionality: Generalize the rule if supported by the alignments, even in the absence of an existing transfer rule for the sub-constituent

Nov 17, 2005Learning-based MT30 Constraint Learning Input: Rules and their Example Sets S::S [NP V NP]  [NP V P NP] {ex1,ex12,ex17,ex26} ((X1::Y1) (X2::Y2) (X3::Y4)) NP::NP [ART ADJ N]  [ART N ART ADJ] {ex2,ex3,ex13} ((X1::Y1) (X1::Y3) (X2::Y4) (X3::Y2)) NP::NP [ART N]  [ART N] {ex4,ex5,ex6,ex8,ex10,ex11} ((X1::Y1) (X2::Y2)) Output: Rules with Feature Constraints: S::S [NP V NP]  [NP V P NP] ((X1::Y1) (X2::Y2) (X3::Y4) (X1 NUM = X2 NUM) (Y1 NUM = Y2 NUM) (X1 NUM = Y1 NUM))

Nov 17, 2005Learning-based MT31 Constraint Learning Goal: add appropriate feature constraints to the acquired rules Methodology: –Preserve general structural transfer –Learn specific feature constraints from example set Seed rules are grouped into clusters of similar transfer structure (type, constituent sequences, alignments) Each cluster forms a version space: a partially ordered hypothesis space with a specific and a general boundary The seed rules in a group form the specific boundary of a version space The general boundary is the (implicit) transfer rule with the same type, constituent sequences, and alignments, but no feature constraints

Nov 17, 2005Learning-based MT32 Constraint Learning: Generalization The partial order of the version space: Definition: A transfer rule tr 1 is strictly more general than another transfer rule tr 2 if all f- structures that are satisfied by tr 2 are also satisfied by tr 1. Generalize rules by merging them: –Deletion of constraint –Raising two value constraints to an agreement constraint, e.g. ((x1 num) = *pl), ((x3 num) = *pl)  ((x1 num) = (x3 num))

Nov 17, 2005Learning-based MT33 Automated Rule Refinement Bilingual informants can identify translation errors and pinpoint the errors A sophisticated trace of the translation path can identify likely sources for the error and do “Blame Assignment” Rule Refinement operators can be developed to modify the underlying translation grammar (and lexicon) based on characteristics of the error source: –Add or delete feature constraints from a rule –Bifurcate a rule into two rules (general and specific) –Add or correct lexical entries See [Font-Llitjos, Carbonell & Lavie, 2005]

Nov 17, 2005Learning-based MT34 Outline Rationale for learning-based MT Roadmap for learning-based MT Framework overview Elicitation Learning transfer Rules Automatic rule refinement Learning Morphology Example prototypes Implications for MT with vast parallel data Conclusions and future directions

Nov 17, 2005Learning-based MT35 Morphology Learning Goal: Unsupervised learning of morphemes and their function from raw monolingual data –Segmentation of words into morphemes –Identification of morphological paradigms (inflections and derivations) –Learning association between morphemes and their function in the language Organize the raw data in the form of a network of paradigm candidate schemes Search the network for a collection of schemes that represent true morphology paradigms of the language Learn mappings between the schemes and features/functions using minimal pairs of elicited data Construct analyzer based on the collection of schemes and the acquired function mappings

Nov 17, 2005Learning-based MT36 Ø.s blame solve Example Vocabulary blame blamed blames roamed roaming roams solve solves solving Ø.s.d blame s blame roam solve e.es blam solv me.mes bla

e.es blam solv e.ed blam es blam solv Ø.s.d blame Ø.s blame solve Ø blame blames blamed roams roamed roaming solve solves solving e.es.ed blam ed blam roam d blame roame Ø.d blame s.d blame s blame roam solve es.ed blam e blam solv me.mes bla me.med bla mes bla me.mes.med bla med bla roa mes.med bla me bla 37

a.as.o.os 43 african, cas, jurídic, l,... a.as.o.os.tro 1 cas a.as.os 50 afectad, cas, jurídic, l,... a.as.o 59 cas, citad, jurídic, l,... a.o.os 105 impuest, indonesi, italian, jurídic,... a.as 199 huelg, incluid, industri, inundad,... a.os 134 impedid, impuest, indonesi, inundad,... as.os 68 cas, implicad, inundad, jurídic,... a.o 214 id, indi, indonesi, inmediat,... as.o 85 intern, jurídic, just, l,... a.tro 2 cas.cen a 1237 huelg, ib, id, iglesi,... as 404 huelg, huelguist, incluid, industri,... os 534 humorístic, human, hígad, impedid,... o 1139 hub, hug, human, huyend,... tro 16 catas, ce, cen, cua,... as.o.os 54 cas, implicad, jurídic, l,... o.os 268 human, implicad, indici, indocumentad,... Spanish Newswire Corpus 40,011 Tokens 6,975 Types 38

a.as.o.os 43 african, cas, jurídic, l,... a.as.o.os.tro 1 cas a.as.os 50 afectad, cas, jurídic, l,... a.as.o 59 cas, citad, jurídic, l,... a.o.os 105 impuest, indonesi, italian, jurídic,... a.as 199 huelg, incluid, industri, inundad,... a.os 134 impedid, impuest, indonesi, inundad,... as.os 68 cas, implicad, inundad, jurídic,... a.o 214 id, indi, indonesi, inmediat,... as.o 85 intern, jurídic, just, l,... a.tro 2 cas.cen a 1237 huelg, ib, id, iglesi,... as 404 huelg, huelguist, incluid, industri,... os 534 humorístic, human, hígad, impedid,... o 1139 hub, hug, human, huyend,... tro 16 catas, ce, cen, cua,... as.o.os 54 cas, implicad, jurídic, l,... o.os 268 human, implicad, indici, indocumentad,... C-Suffixes C-Stems Level 5 = 5 C-suffixes C-Stem Type Count 39

a.as.o.os 43 african, cas, jurídic, l,... a.as.o.os.tro 1 cas a.tro 2 cas.cen tro 16 catas, ce, cen, cua,... Adjective Inflection Class 40 a.as.os 50 afectad, cas, jurídic, l,... a.as.o 59 cas, citad, jurídic, l,... a.o.os 105 impuest, indonesi, italian, jurídic,... a.as 199 huelg, incluid, industri, inundad,... a.os 134 impedid, impuest, indonesi, inundad,... as.os 68 cas, implicad, inundad, jurídic,... a.o 214 id, indi, indonesi, inmediat,... as.o 85 intern, jurídic, just, l,... a 1237 huelg, ib, id, iglesi,... as 404 huelg, huelguist, incluid, industri,... os 534 humorístic, human, hígad, impedid,... o 1139 hub, hug, human, huyend,... as.o.os 54 cas, implicad, jurídic, l,... o.os 268 human, implicad, indici, indocumentad,... From the spurious c-suffix “tro”

a.as.o.os.tro 1 cas a.tro 2 cas.cen tro 16 catas, ce, cen, cua,... a.as.o.os 43 african, cas, jurídic, l,... a.as.os 50 afectad, cas, jurídic, l,... a.as.o 59 cas, citad, jurídic, l,... a.o.os 105 impuest, indonesi, italian, jurídic,... a.as 199 huelg, incluid, industri, inundad,... a.os 134 impedid, impuest, indonesi, inundad,... as.os 68 cas, implicad, inundad, jurídic,... a.o 214 id, indi, indonesi, inmediat,... as.o 85 intern, jurídic, just, l,... a 1237 huelg, ib, id, iglesi,... as 404 huelg, huelguist, incluid, industri,... os 534 humorístic, human, hígad, impedid,... o 1139 hub, hug, human, huyend,... as.o.os 54 cas, implicad, jurídic, l,... o.os 268 human, implicad, indici, indocumentad, Decreasing C-Stem Count Increasing C-Suffix Count Basic Search Procedure

Nov 17, 2005Learning-based MT42 Outline Rationale for learning-based MT Roadmap for learning-based MT Framework overview Elicitation Learning transfer Rules Automatic rule refinement Learning Morphology Example prototypes Implications for MT with vast parallel data Conclusions and future directions

Nov 17, 2005Learning-based MT43 AVENUE Prototypes General XFER framework under development for past three years Prototype systems so far: –German-to-English, Dutch-to-English –Chinese-to-English –Hindi-to-English –Hebrew-to-English In progress or planned: –Mapudungun-to-Spanish –Quechua-to-Spanish –Arabic-to-English –Native-Brazilian languages to Brazilian Portuguese

Nov 17, 2005Learning-based MT44 Challenges for Hebrew MT Paucity in existing language resources for Hebrew –No publicly available broad coverage morphological analyzer –No publicly available bilingual lexicons or dictionaries –No POS-tagged corpus or parse tree-bank corpus for Hebrew –No large Hebrew/English parallel corpus Scenario well suited for CMU transfer-based MT framework for languages with limited resources

Nov 17, 2005Learning-based MT45 Hebrew-to-English MT Prototype Initial prototype developed within a two month intensive effort Accomplished: –Adapted available morphological analyzer –Constructed a preliminary translation lexicon –Translated and aligned Elicitation Corpus –Learned XFER rules –Developed (small) manual XFER grammar as a point of comparison –System debugging and development –Evaluated performance on unseen test data using automatic evaluation metrics

Transfer Engine English Language Model Transfer Rules {NP1,3} NP1::NP1 [NP1 "H" ADJ] -> [ADJ NP1] ((X3::Y1) (X1::Y2) ((X1 def) = +) ((X1 status) =c absolute) ((X1 num) = (X3 num)) ((X1 gen) = (X3 gen)) (X0 = X1)) Translation Lexicon N::N |: ["$WR"] -> ["BULL"] ((X1::Y1) ((X0 NUM) = s) ((Y0 lex) = "BULL")) N::N |: ["$WRH"] -> ["LINE"] ((X1::Y1) ((X0 NUM) = s) ((Y0 lex) = "LINE")) Source Input בשורה הבאה Decoder English Output in the next line Translation Output Lattice (0 1 (1 1 (2 2 (1 2 "THE (0 2 "IN (0 4 "IN THE NEXT Preprocessing Morphology

Nov 17, 2005Learning-based MT47 Morphology Example Input word: B$WRH | B$WRH | |-----B-----|$WR|--H--| |--B--|-H--|--$WRH---|

Nov 17, 2005Learning-based MT48 Morphology Example Y0: ((SPANSTART 0) Y1: ((SPANSTART 0) Y2: ((SPANSTART 1) (SPANEND 4) (SPANEND 2) (SPANEND 3) (LEX B$WRH) (LEX B) (LEX $WR) (POS N) (POS PREP)) (POS N) (GEN F) (GEN M) (NUM S) (NUM S) (STATUS ABSOLUTE)) (STATUS ABSOLUTE)) Y3: ((SPANSTART 3) Y4: ((SPANSTART 0) Y5: ((SPANSTART 1) (SPANEND 4) (SPANEND 1) (SPANEND 2) (LEX $LH) (LEX B) (LEX H) (POS POSS)) (POS PREP)) (POS DET)) Y6: ((SPANSTART 2) Y7: ((SPANSTART 0) (SPANEND 4) (SPANEND 4) (LEX $WRH) (LEX B$WRH) (POS N) (POS LEX)) (GEN F) (NUM S) (STATUS ABSOLUTE))

Nov 17, 2005Learning-based MT49 Sample Output (dev-data) maxwell anurpung comes from ghana for israel four years ago and since worked in cleaning in hotels in eilat a few weeks ago announced if management club hotel that for him to leave israel according to the government instructions and immigration police in a letter in broken english which spread among the foreign workers thanks to them hotel for their hard work and announced that will purchase for hm flight tickets for their countries from their money

Nov 17, 2005Learning-based MT50 Evaluation Results Test set of 62 sentences from Haaretz newspaper, 2 reference translations SystemBLEUNISTPRMETEOR No Gram Learned Manual

Nov 17, 2005Learning-based MT51 Hebrew-English: Test Suite Evaluation GrammarBLEUMETEOR Baseline (NoGram) Learned Grammar Manual Grammar

Nov 17, 2005Learning-based MT52 Outline Rationale for learning-based MT Roadmap for learning-based MT Framework overview Elicitation Learning transfer Rules Automatic rule refinement Learning Morphology Example prototypes Implications for MT with vast parallel data Conclusions and future directions

Nov 17, 2005Learning-based MT53 Implications for MT with Vast Amounts of Parallel Data Learning word/short-phrase translations vs. learning long phrase-to-phrase translations Phrase-to-phrase MT ill suited for long-range reorderings  ungrammatical output Recent work on hierarchical Stat-MT [Chiang, 2005] and parsing-based MT [Melamed et al, 2005] Learning general tree-to-tree syntactic mappings is equally problematic: –Meaning is a hybrid of complex, non-compositional phrases embedded within a syntactic structure –Some constituents can be translated in isolation, others require contextual mappings

Nov 17, 2005Learning-based MT54 Implications for MT with Vast Amounts of Parallel Data Our approach for learning transfer rules is applicable to the large data scenario, subject to solutions for several challenges: –No elicitation corpus  break-down parallel sentences into reasonable learning examples –Working with less reliable automatic word alignments rather than manual alignments –Effective use of reliable parse structures for ONE language (i.e. English) and automatic word alignments in order to decompose the translation of a sentence into several compositional rules. –Effective scoring of resulting very large transfer grammars, and scaled up transfer + decoding

Nov 17, 2005Learning-based MT55 Implications for MT with Vast Amounts of Parallel Data Example: 他 经常 与 江泽民 总统 通 电话 He freq with J Zemin Pres via phone He freq talked with President J Zemin over the phone

Nov 17, 2005Learning-based MT56 Implications for MT with Vast Amounts of Parallel Data Example: 他 经常 与 江泽民 总统 通 电话 He freq with J Zemin Pres via phone He freq talked with President J Zemin over the phone NP1 NP2 NP3

Nov 17, 2005Learning-based MT57 Conclusions There is hope yet for wide-spread MT between many of the worlds language pairs MT offers a fertile yet extremely challenging ground for learning-based approaches that leverage from diverse sources of information: –Syntactic structure of one or both languages –Word-to-word correspondences –Decomposable units of translation –Statistical Language Models Provides a feasible solution to MT for languages with limited resources Extremely promising approach for addressing the fundamental weaknesses in current corpus-based MT for languages with vast resources

Nov 17, 2005Learning-based MT58 Future Research Directions Automatic Transfer Rule Learning: –In the “large-data” scenario: from large volumes of uncontrolled parallel text automatically word-aligned –In the absence of morphology or POS annotated lexica –Learning mappings for non-compositional structures –Effective models for rule scoring for Decoding: using scores at runtime Pruning the large collections of learned rules –Learning Unification Constraints Integrated Xfer Engine and Decoder –Improved models for scoring tree-to-tree mappings, integration with LM and other knowledge sources in the course of the search

Nov 17, 2005Learning-based MT59 Future Research Directions Automatic Rule Refinement Morphology Learning Feature Detection and Corpus Navigation …

Nov 17, 2005Learning-based MT60

Nov 17, 2005Learning-based MT61 Mapudungun-to-Spanish Example Mapudungun pelafiñ Maria Spanish No vi a María English I didn’t see Maria

Nov 17, 2005Learning-based MT62 Mapudungun-to-Spanish Example Mapudungun pelafiñ Maria pe-la-fi-ñMaria see-neg-3.obj-1.subj.indicativeMaria Spanish No vi a María negsee.1.subj.past.indicativeaccMaria English I didn’t see Maria

Nov 17, 2005Learning-based MT63 V pe pe-la-fi-ñ Maria

Nov 17, 2005Learning-based MT64 V pe pe-la-fi-ñ Maria VSuff la Negation = +

Nov 17, 2005Learning-based MT65 V pe pe-la-fi-ñ Maria VSuff la VSuffG Pass all features up

Nov 17, 2005Learning-based MT66 V pe pe-la-fi-ñ Maria VSuff la VSuffG VSuff fi object person = 3

Nov 17, 2005Learning-based MT67 V pe pe-la-fi-ñ Maria VSuff la VSuffGVSuff fi VSuffG Pass all features up from both children

Nov 17, 2005Learning-based MT68 V pe pe-la-fi-ñ Maria VSuff la VSuffGVSuff fi VSuffGVSuff ñ person = 1 number = sg mood = ind

Nov 17, 2005Learning-based MT69 V pe pe-la-fi-ñ Maria VSuff la VSuffGVSuff fi VSuffGVSuff ñ Pass all features up from both children VSuffG

Nov 17, 2005Learning-based MT70 V V pe pe-la-fi-ñ Maria VSuff la VSuffGVSuff fi VSuffGVSuff ñ Pass all features up from both children VSuffG Check that: 1) negation = + 2) tense is undefined

Nov 17, 2005Learning-based MT71 V pe pe-la-fi-ñ Maria VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG V NP N Maria N person = 3 number = sg human = +

Nov 17, 2005Learning-based MT72 Pass features up from V pe pe-la-fi-ñ Maria VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V Check that NP is human = + V VP

Nov 17, 2005Learning-based MT73 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S

Nov 17, 2005Learning-based MT74 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V Pass all features to Spanish side

Nov 17, 2005Learning-based MT75 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V Pass all features down

Nov 17, 2005Learning-based MT76 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V Pass object features down

Nov 17, 2005Learning-based MT77 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V Accusative marker on objects is introduced because human = +

Nov 17, 2005Learning-based MT78 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V VP::VP [VBar NP] -> [VBar "a" NP] ((X1::Y1) (X2::Y3) ((X2 type) = (*NOT* personal)) ((X2 human) =c +) (X0 = X1) ((X0 object) = X2) (Y0 = X0) ((Y0 object) = (X0 object)) (Y1 = Y0) (Y3 = (Y0 object)) ((Y1 objmarker person) = (Y3 person)) ((Y1 objmarker number) = (Y3 number)) ((Y1 objmarker gender) = (Y3 ender)))

Nov 17, 2005Learning-based MT79 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V V“no” Pass person, number, and mood features to Spanish Verb Assign tense = past

Nov 17, 2005Learning-based MT80 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V V“no” Introduced because negation = +

Nov 17, 2005Learning-based MT81 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V V“no” ver

Nov 17, 2005Learning-based MT82 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V V“no” ver vi person = 1 number = sg mood = indicative tense = past

Nov 17, 2005Learning-based MT83 V pe Transfer to Spanish: Top-Down VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V V“no” vi N María N Pass features over to Spanish side

Nov 17, 2005Learning-based MT84 V pe I Didn’t see Maria VSuff la VSuffGVSuff fi VSuffGVSuff ñ VSuffG NP N Maria N S V VP S NP“a” V V“no” vi N María N

Nov 17, 2005Learning-based MT85