Combining Models for the Alignment of Parallel Syntactic Trees

The alignment of syntactic trees is the task of aligning the internal and leaf nodes of two sentences in different languages structured as trees. The output of the alignment can be used, for instance, as knowledge resource for learning translation rules (for rule-based machine translation systems) or models (for statistical machine translation systems). This paper presents some experiments carried out based on two syntactic tree alignment algorithms presented in [Lavie et al. 2008] and [Tinsley et al. 2007]. Aiming at improving the performance of internal nodes alignment, some approaches for combining the output of these two algorithms were evaluated in Brazilian Portuguese and English parallel trees.