Improving statistical MT by coupling reordering and decoding

In this paper we describe an elegant and efficient approach to coupling reordering and decoding in statistical machine translation, where the n-gram translation model is also employed as distortion model. The reordering search problem is tackled through a set of linguistically motivated rewrite rules, which are used to extend a monotonic search graph with reordering hypotheses. The extended graph is traversed in the global search when a fully informed decision can be taken. Further experiments show that the n-gram translation model can be successfully used as reordering model when estimated with reordered source words. Experiments are reported on the Europarl task (Spanish–English and English–Spanish). Results are presented regarding translation accuracy and computational efficiency, showing significant improvements in translation quality with respect to monotonic search for both translation directions at a very low computational cost.

[1]  L BergerAdam,et al.  A maximum entropy approach to natural language processing , 1996 .

[2]  Philipp Koehn,et al.  Explorer Edinburgh System Description for the 2005 IWSLT Speech Translation Evaluation , 2005 .

[3]  Hermann Ney,et al.  Discriminative Reordering Models for Statistical Machine Translation , 2006, WMT@HLT-NAACL.

[4]  Marc Dymetman,et al.  Translating with Non-contiguous Phrases , 2005, HLT.

[5]  Taro Watanabe,et al.  Left-to-Right Target Generation for Hierarchical Phrase-Based Translation , 2006, ACL.

[6]  A. Gispert,et al.  Reordered Search, and Tuple Unfolding for Ngram-based SMT , 2005, MTSUMMIT.

[7]  José B. Mariño,et al.  REORDERING EXPERIMENTS FOR N-GRAM-BASED SMT , 2006, 2006 IEEE Spoken Language Technology Workshop.

[8]  David Chiang,et al.  A Hierarchical Phrase-Based Model for Statistical Machine Translation , 2005, ACL.

[9]  Hermann Ney,et al.  Phrase-Based Statistical Machine Translation , 2002, KI.

[10]  Xavier Carreras,et al.  FreeLing: An Open-Source Suite of Language Analyzers , 2004, LREC.

[11]  Salim Roukos,et al.  Bleu: a Method for Automatic Evaluation of Machine Translation , 2002, ACL.

[12]  John Cocke,et al.  A Statistical Approach to Machine Translation , 1990, CL.

[13]  Sergei Nirenburg,et al.  Readings in Machine Translation , 2003 .

[14]  Chris Quirk,et al.  Dependency Treelet Translation: Syntactically Informed Phrasal SMT , 2005, ACL.

[15]  Tong Zhang,et al.  A Localized Prediction Model for Statistical Machine Translation , 2005, ACL.

[16]  Hermann Ney,et al.  POS-based Word Reorderings for Statistical Machine Translation , 2006, LREC.

[17]  Dekai Wu,et al.  Stochastic Inversion Transduction Grammars and Bilingual Parsing of Parallel Corpora , 1997, CL.

[18]  George R. Doddington,et al.  Automatic Evaluation of Machine Translation Quality Using N-gram Co-Occurrence Statistics , 2002 .

[19]  Thorsten Brants,et al.  TnT – A Statistical Part-of-Speech Tagger , 2000, ANLP.

[20]  Shankar Kumar,et al.  Local Phrase Reordering Models for Statistical Machine Translation , 2005, HLT.

[21]  Andreas Stolcke,et al.  SRILM - an extensible language modeling toolkit , 2002, INTERSPEECH.

[22]  Christoph Tillmann,et al.  A Unigram Orientation Model for Statistical Machine Translation , 2004, NAACL.

[23]  S. Mansoor Sarwar,et al.  Engineering Quicksort , 1996, Comput. Lang..

[24]  José B. Mariño,et al.  N-gram-based Machine Translation , 2006, CL.

[25]  Kevin Knight,et al.  A Decoder for Syntax-based Statistical MT , 2002, ACL.

[26]  José B. Mariño,et al.  Finite-state-based and phrase-based statistical machine translation , 2004, INTERSPEECH.

[27]  Hermann Ney,et al.  Discriminative Training and Maximum Entropy Models for Statistical Machine Translation , 2002, ACL.

[28]  Dekai Wu,et al.  A Polynomial-Time Algorithm for Statistical Machine Translation , 1996, ACL.

[29]  Fei Xia,et al.  Improving a Statistical MT System with Automatically Learned Rewrite Patterns , 2004, COLING.

[30]  Adam L. Berger,et al.  A Maximum Entropy Approach to Natural Language Processing , 1996, CL.

[31]  Josep M. Crego,et al.  Integration of POStag-based Source Reordering into SMT Decoding by an Extended Search Graph , 2006, AMTA.

[32]  José B. Mariño,et al.  An n-gram-based statistical machine translation decoder , 2005, INTERSPEECH.

[33]  Philippe Langlais,et al.  Phrase-Based SMT with Shallow Tree-Phrases , 2006, WMT@HLT-NAACL.

[34]  Kevin Knight,et al.  Decoding Complexity in Word-Replacement Translation Models , 1999, Comput. Linguistics.

[35]  John A. Nelder,et al.  A Simplex Method for Function Minimization , 1965, Comput. J..

[36]  José B. Mariño,et al.  N-gram-based versus phrase-based statistical machine translation , 2005, IWSLT.

[37]  Masaaki Nagata,et al.  A Clustered Global Phrase Reordering Model for Statistical Machine Translation , 2006, ACL.

[38]  Marta R. Costa-jussà,et al.  Statistical Machine Reordering , 2006, EMNLP.

[39]  Hermann Ney,et al.  Improved Statistical Alignment Models , 2000, ACL.

[40]  Philipp Koehn,et al.  Clause Restructuring for Statistical Machine Translation , 2005, ACL.

[41]  Robert L. Mercer,et al.  The Mathematics of Statistical Machine Translation: Parameter Estimation , 1993, CL.

[42]  Franz Josef Och,et al.  Minimum Error Rate Training in Statistical Machine Translation , 2003, ACL.

[43]  Sergei Nirenburg,et al.  A Statistical Approach to Machine Translation , 2003 .

[44]  Hermann Ney,et al.  Novel Reordering Approaches in Phrase-Based Statistical Machine Translation , 2005, ParallelText@ACL.

[45]  José A. R. Fonollosa,et al.  Ngram-based versus Phrase-based Statistical Machine Translation , 2005, IWSLT.