Abstract
When aligning very different language pairs, the most important needs are the use of structural information and the capability of generating one-to-many or many-to-many correspondences. In this paper, we propose a novel phrase alignment method which models word or phrase dependency relations in dependency tree structures of source and target languages. The dependency relation model is a kind of tree-based reordering model, and can handle non-local reorderings which sequential word-based models often cannot handle properly. The model is also capable of estimating phrase correspondences automatically without any heuristic rules. Experimental results of alignment show that our model could achieve F-measure 8.5 points higher than the conventional word alignment model with symmetrization algorithms.