1. A translation method comprising: receiving an input query in a source language; and outputting a target query, the target query being based on a translation of the input query into a target language, different from the source language, with a machine translation system which has been trained on representations of features of translated queries, the translated queries having been generated by translation of an original query in the source language into the target language and a measure of information retrieval performance of each the translated queries, for each of a set of original queries.