19. The system of claim 16 , wherein determining that the user is likely no longer within the particular context comprises determining that the user is likely in a different context.
16. An automated speech recognizer (ASR) system comprising: one or more computers comprising (i) a context selector, (ii) a language model biaser, (iii) an ASR, (iv) a particular language model, and (v) a previously biased language model, and including one or more storage devices storing instructions that when executed by the one or more computers cause the one or more computers to perform operations comprising: receiving audio data corresponding to an utterance of a user; determining, by the context selector, that the user is likely no longer within a particular context that is associated the previously biased language model; in response to determining that the user is likely no longer within a particular context that is associated with the previously biased language model, selecting, by the language model biaser, the particular language model for use in transcribing utterances; after selecting the baseline language model, generating, by the ASR, a transcription of the utterance using the particular language model; and providing a representation of the transcription for output.