Paper: Generalizing Local and Non-Local Word-Reordering Patterns for Syntax-Based Machine Translation

ACL ID D08-1060
Title Generalizing Local and Non-Local Word-Reordering Patterns for Syntax-Based Machine Translation
Venue Conference on Empirical Methods in Natural Language Processing
Session Main Conference
Year 2008
Authors

Syntactic word reordering is essential for translations across different grammar struc- tures between syntactically distant language- pairs. In this paper, we propose to em- bed local and non-local word reordering de- cisions in a synchronous context free gram- mar, and leverages the grammar in a chart- based decoder. Local word-reordering is ef- fectively encoded in Hiero-like rules; whereas non-local word-reordering, which allows for long-range movements of syntactic chunks, is represented in tree-based reordering rules, which contain variables correspond to source- side syntactic constituents. We demonstrate how these rules are learned from parallel cor- pora. Our proposed shallow Tree-to-String rules show significant improvements in trans- lation quality across different test sets.