A syntax-driven bracketing model for phrase-based translation

Syntactic analysis influences the way in which the source sentence is translated. Previous efforts add syntactic constraints to phrase-based translation by directly rewarding/punishing a hypothesis when-ever it matches/violates source-side con-stituents. We present a new model that automatically learns syntactic constraints, including but not limited to constituent matching/violation, from training corpus. The model brackets a source phrase as to whether it satisfies the learnt syntac-tic constraints. The bracketed phrases are then translated as a whole unit by the de-coder. Experimental results and analy-sis show that the new model outperforms other previous methods and achieves a substantial improvement over the baseline which is not syntactically informed.