1. A method for generating word alignments from pairs of aligned text strings comprising: from a corpus of text strings, receiving a pair of text strings comprising a first text string in a first language and a second text string in a second language; with a first alignment tool, generating a first alignment between the first and second text strings which creates links between the first and second text string, each link linking a single token of the first text string to a single token of the second text string, the tokens of the first and second text strings including words; with a second alignment tool, generating a second alignment between the first and second text strings which creates links between the first and second text strings, each link linking at least one token of the first text string to at least one token of the second text string, and generating a modified first alignment by selectively modifying links in the first alignment which include a word which is infrequent in the corpus, based on links generated in the second alignment, the selective modification of the links comprising identifying links in the first alignment to be retained which include the infrequent word and a linked target word where there is a corresponding link present in the second alignment which includes the infrequent word and the same linked target word and identifying for removal, at least a portion of the links in the first alignment which include the infrequent word and a linked target word for which there is no corresponding link between the infrequent word and the linked target word in the second alignment, wherein the generation of at least one of the first, second, and modified alignments is performed with a computer processor.
15. The method of claim 1 , further comprising extracting bi-phrases based on the links in the modified alignment.