Partitioning Parallel Documents Using Binary Segmentation

In statistical machine translation, large numbers of parallel sentences are required to train the model parameters. However, plenty of the bilingual language resources available on web are aligned only at the document level. To exploit this data, we have to extract the bilingual sentences from these documents. The common method is to break the documents into segments using predefined anchor words, then these segments are aligned. This approach is not error free, incorrect alignments may decrease the translation quality. We present an alternative approach to extract the parallel sentences by partitioning a bilingual document into two pairs. This process is performed recursively until all the sub-pairs are short enough. In experiments on the Chinese-English FBIS data, our method was capable of producing translation results comparable to those of a state-of-the-art sentence aligner. Using a combination of the two approaches leads to better translation performance.