9. A system comprising: one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising: receiving a request to update an existing speech recognition model for recognizing a particular term by a speech recognizer on a mobile device, wherein the request references a textual representation of the particular term and includes a recording of a user of the mobile device speaking the particular term or a set of features extracted from the recording, wherein the request specifies an updated speech recognition model type to be generated, and wherein the updated speech recognition type is a different speech recognition model type than the speech recognition model type of the existing speech recognition model; generating the updated speech recognition model for recognizing the particular term based on the request; and transmitting the updated speech recognition model for recognizing the particular term to the mobile device, as a replacement for the existing speech recognition model for recognizing the particular term.
14. The system of claim 9 , wherein the operations comprise: augmenting a training corpus with the term, wherein the updated existing speech recognition model is generated using the augmented training corpus.