Lessons from NRC′s Portage System at WMT 2010

NRC’s Portage system participated in the English-French (E-F) and French-English (F-E) translation tasks of the ACL WMT 2010 evaluation. The most notable improvement over earlier versions of Portage is an efficient implementation of lattice MERT. While Portage has typically performed well in Chinese to English MT evaluations, most recently in the NIST09 evaluation, our participation in WMT 2010 revealed some interesting differences between Chinese-English and E-F/F-E translation, and alerted us to certain weak spots in our system. Most of this paper discusses the problems we found in our system and ways of fixing them. We learned several lessons that we think will be of general interest.