8. A device-comprising: at least one microphone for receiving an utterance in a first language from a user; and a speech translation system in communication with the at least one microphone, wherein the speech translation system is for translating the utterance into a second language, and wherein the speech translation system comprises: a first automatic speech recognition module for the first language for recognizing speech in the utterance in the first language; a first machine translation module in communication with the first speech recognition module, wherein the first machine translation module is for translating the recognized speech in the first language, recognized by the first speech recognition module, into the second language; and; a user interface in communication with the speech translation system for outputting the translation of the utterance in the second language determined by the first machine translation module; wherein the speech translation system is configured to: receive from the user, the utterance in the first language that is to be translated by the speech translation system from the first language to the second language; receive an indication to add a new word in the first language to the first recognition lexicon of the first automatic speech recognition module of the speech translation system; determine for the new word, by a processor, word class information, a pronunciation in the first language, the translation in the second language, and a pronunciation in the second language; add the new word, the determined word class information and the determined pronunciation in the first language to the first recognition lexicon of the first language of the first automatic speech recognition module; and add the new word, the determined word class information, the determined translation in the second language and the pronunciation of the translation in the second language, to the first machine translation module.
13. The device of claim 8 , wherein the user is prompted to verify the word class information, pronunciation in the first language, and translation in the second language before the new word is added to the first machine translation module associated with the first language of the speech translation system.