8. A computer-implemented selection method, comprising acts of: receiving a set of trained in-domain language models, one for each language of multi-lingual sentences based on an in-domain corpus and a set of trained out-domain language models, one for each language of multi-lingual sentences based on an out-domain corpus; computing similarity scores for each of the sentences of the out-domain corpus, the scores obtained using a similarity measure as applied to the sentences against the in-domain language model and the out-domain language model; ranking the sentences based on the scores; selecting a set of sentences from the out-domain corpus based on the ranked scores; building a translation model based on either the set selected from the out-domain corpus, or a combination of the set selected from the out-domain corpus and the in-domain corpus; and utilizing a processor that executes instructions stored in memory to perform at least one of the acts of computing, ranking, selecting, or building.
8. A computer-implemented selection method, comprising acts of: receiving a set of trained in-domain language models, one for each language of multi-lingual sentences based on an in-domain corpus and a set of trained out-domain language models, one for each language of multi-lingual sentences based on an out-domain corpus; computing similarity scores for each of the sentences of the out-domain corpus, the scores obtained using a similarity measure as applied to the sentences against the in-domain language model and the out-domain language model; ranking the sentences based on the scores; selecting a set of sentences from the out-domain corpus based on the ranked scores; building a translation model based on either the set selected from the out-domain corpus, or a combination of the set selected from the out-domain corpus and the in-domain corpus; and utilizing a processor that executes instructions stored in memory to perform at least one of the acts of computing, ranking, selecting, or building. 11. The method of claim 8 , further comprising ranking the sentences for selection according to similarity scores, the scores obtained as a difference of the similarity scores according to the in-domain language model and, a similarity score according to the out-domain language model on a source side or a target side.