Inferring paraphrases for a highly inflected language from a monolingual corpus

Abstract

We suggest a new technique for deriving paraphrases from a monolingual corpus, supported by a relatively small set of comparable documents. Two somewhat similar phrases that each occur in one of a pair of documents dealing with the same incident are taken as potential paraphrases, which are evaluated based on the contexts in which they appear in the larger monolingual corpus. We apply this technique to Arabic, a highly inflected language, for improving an Arabic-to-English statistical translation system. The paraphrases are provided to the translation system formatted as a word lattice, each assigned with a score reflecting its equivalence level. We experiment with the system on different configurations, resulting in encouraging results: our best system shows an increase of 1.73 (5.49%) in BLEU. © 2014 Springer-Verlag Berlin Heidelberg.