Translation of Multiword Expressions Using Parallel Suffix Arrays

Accurately translating multiword expres- sions is important to obtain good per- formance in machine translation, cross- language information retrieval, and other multilingual tasks in human language technology. Existing approaches to induc- ing translation equivalents of multiword units have focused on agglomerating in- dividual words or on aligning words in a statistical machine translation system. We present a different approach based upon information theoretic heuristics and the exact counting of frequencies of occur- rence of multiword strings in aligned par- allel corpora. We are applying a technique introduced by Yamamoto and Church that uses suffix arrays and longest common prefix arrays. Evaluation of the method in multiple language pairs was performed using bilingual lexicons of domain- specific terminology as a gold standard. We found that performance of 50-70%, as measured by mean reciprocal rank, can be obtained for terms that occur more than 10 or so times.