7. A system comprising: a processor; and a computer-readable storage medium having instructions stored which, when executed by the processor, cause the processor to perform operations comprising: detecting, at a mobile device, a change in geographic location of the mobile device to yield a new context of a speech dialog; identifying a plurality of speech models on a remote server; calculating a likelihood score for each speech model in the plurality of speech models, wherein the likelihood score indicates a compatibility of each speech model to recognize speech in the speech dialog in the new context to yield likelihood scores; selecting a speech model from the plurality of speech models according to the likelihood scores; determining that a local storage on the mobile device has insufficient space to store the speech model; calculating local likelihood scores of local speech models stored in the local storage, wherein the local likelihood scores indicate a probability of each local speech model to recognize the speech in the speech dialog with the new context to yield a respective scored local speech model; and removing the respective scored local speech model having a lowest likelihood score of the local likelihood scores until a sufficient space for the speech model is made available on the mobile device.
7. A system comprising: a processor; and a computer-readable storage medium having instructions stored which, when executed by the processor, cause the processor to perform operations comprising: detecting, at a mobile device, a change in geographic location of the mobile device to yield a new context of a speech dialog; identifying a plurality of speech models on a remote server; calculating a likelihood score for each speech model in the plurality of speech models, wherein the likelihood score indicates a compatibility of each speech model to recognize speech in the speech dialog in the new context to yield likelihood scores; selecting a speech model from the plurality of speech models according to the likelihood scores; determining that a local storage on the mobile device has insufficient space to store the speech model; calculating local likelihood scores of local speech models stored in the local storage, wherein the local likelihood scores indicate a probability of each local speech model to recognize the speech in the speech dialog with the new context to yield a respective scored local speech model; and removing the respective scored local speech model having a lowest likelihood score of the local likelihood scores until a sufficient space for the speech model is made available on the mobile device. 11. The system of claim 7 , the computer-readable storage medium having additional instructions stored which, when executed by the processor, cause the processor to perform operations comprising: determining that an existing speech model stored on the mobile device has a lower likelihood score than the speech model; and removing the existing speech model from local storage on the mobile device.