14. A method for query suggestion performed by a processor executing computer-executable instructions stored on a memory device, the method comprising: receiving an input query in source language; providing a plurality of candidate queries in target language, at least part of the plurality of candidate queries in target language being selected from a query log of a search engine; evaluating the plurality of candidate queries in target language at least partly by deducing a monolingual similarity between the input query in source language and a translation of a respective candidate query from target language to source language; ranking the plurality of candidate queries in target language using a cross-lingual query similarity score, the cross-lingual query similarity score being based on a plurality of features and a weight of each feature in calculating the cross-lingual query similarity score; and from top ranking candidate queries in target language, suggesting a query in target language as a cross-lingual query at least partly based on click-through information of documents selected by users for the plurality of candidate queries in target language.
15. The method as recited in claim 14 , wherein the providing the plurality of candidate queries in target language comprises: ranking potential query translations of the input query in source language using term-term cohesion, the potential query translations being constructed from a bilingual dictionary; selecting a set of top query translations based on ranking result; and for each top query translation, retrieving from the query log at least one query containing the same keywords as the top query translation.