Paper: Bilingually-Constrained (Monolingual) Shift-Reduce Parsing

ACL ID D09-1127
Title Bilingually-Constrained (Monolingual) Shift-Reduce Parsing
Venue Conference on Empirical Methods in Natural Language Processing
Session Main Conference
Year 2009

Jointly parsing two languages has been shown to improve accuracies on either or both sides. However, its search space is much bigger than the monolingual case, forcing existing approaches to employ complicated modeling and crude approxi- mations. Here we propose a much simpler alternative, bilingually-constrained mono- lingual parsing, where a source-language parser learns to exploit reorderings as ad- ditional observation, but not bothering to build the target-side tree as well. We show specifically how to enhance a shift-reduce dependency parser with alignment fea- tures to resolve shift-reduce conflicts. Ex- periments on the bilingual portion of Chi- nese Treebank show that, with just 3 bilin- gual features, we can improve parsing ac- curacies by 0.6% (absolute) for both En- glish and C...