We propose semantic role features for a Tree-to-String transducer to model the reordering/deletion of source-side semantic roles. These semantic features, as well as the Tree-to-String templates, are trained based on a conditional log-linear model and are shown to significantly outperform systems trained based on Max-Likelihood and EM. We also show significant improvement in sentence fluency by using the semantic role features in the log-linear model, based on manual evaluation.
REF add features extracted from the source sentences annotated with semantic role labels in a tree-to-string SMT model.
Semantic Role Features for Machine Translation
COLING
Computer Science