1. A method for building a translation lexicon from non-parallel corpora by a machine translation system, the method comprising: identifying identically spelled words in a first corpus and a second corpus, the first corpus including words in a first language and the second corpus including words in a second language, wherein the first corpus and the second corpus are non-parallel and are accessed by the machine translation system; generating a seed lexicon by the machine translation system, the seed lexicon including identically spelled words; and expanding the seed lexicon by the machine translation system by identifying possible translations of words in the first and second corpora using one or more clues.