1. A translation method comprising: receiving an input query in a source language; translating the input query with a phrase-based statistical machine translation system to generate a set of candidate translations of the input query in a target language; extracting a set of features from each of the candidate translations in the set, the set of features including at least one domain specific feature which is based on a comparison of at least one term in the candidate translation with words in a domain-specific corpus of documents; scoring each of the candidate translations with a scoring function in which the extracted features are weighted with respective weights, the weights having been learned on: features extracted from translated queries, each of the translated queries having been generated by translation of an original query from a set of original queries into the target language with a machine translation system, and a measure of information retrieval performance of each of the translated queries, for each original query in the set of original queries, the information retrieval performance of each translated query being based on a relevance score, with respect to the respective original query, for documents in a set of documents that have been retrieved in response to the translated query; and outputting a target query in the target language based on the scores of the candidate translations.