Paper: Quasi-Synchronous Phrase Dependency Grammars for Machine Translation

ACL ID D11-1044
Title Quasi-Synchronous Phrase Dependency Grammars for Machine Translation
Venue Conference on Empirical Methods in Natural Language Processing
Session Main Conference
Year 2011
Authors

We present a quasi-synchronous dependency grammar (Smith and Eisner, 2006) for ma- chine translation in which the leaves of the tree are phrases rather than words as in pre- vious work (Gimpel and Smith, 2009). This formulation allows us to combine structural components of phrase-based and syntax-based MT in a single model. We describe a method of extracting phrase dependencies from paral- lel text using a target-side dependency parser. For decoding, we describe a coarse-to-fine ap- proach based on lattice dependency parsing of phrase lattices. We demonstrate performance improvements for Chinese-English and Urdu- English translation over a phrase-based base- line. We also investigate the use of unsuper- vised dependency parsers, reporting encourag- ing preliminary results.