1. A method comprising: receiving from a user an utterance in a first language including a first term; by a speech translation system, translating the utterance from the first language into a second language; receiving an indication from the user to initiate a user customization process for customizing one or more modules of the speech translation system to the user; and under the user customization process: receiving an indication from the user to add the first term to one or more modules of the speech translation system; in response to the received indication from the user, determining word class information for the first term; adding, by the speech translation system, the first term, the determined word class information, and at least a portion of the translation of the utterance in the second language to a first machine translation module associated with the first language of the speech translation system; and adding the first term and the at least a portion of the translation of the utterance in the second language to a shared database for a community such that the customization performed by the user is available for use by other users of the community in translations by the speech translation system.