CMU Multi-Engine Machine Translation for WMT 2010

This paper describes our submission, cmu-heafield-combo, to the WMT 2010 machine translation system combi-nation task. Using constrained resources, we participated in all nine language pairs, namely translating English to and from Czech, French, German, and Spanish as well as combining English translations from multiple languages. Combination proceeds by aligning all pairs of system outputs then navigating the aligned out-puts from left to right where each path is a candidate combination. Candidate com-binations are scored by their length, agree-ment with the underlying systems, and a language model. On tuning data, improve-ment in BLEU over the best system de-pends on the language pair and ranges from 0.89 % to 5.57 % with mean 2.37%.