1. A computer-implemented method comprising: accessing, by a computer system, a search history that identifies one or more search queries that were previously submitted to one or more search services by one or more computing devices that are associated with a user; identifying, based at least in part on the search queries included in the search history, a geographic location to which future voice input from the user is likely to relate, the geographic location being identified independent of a current geographic location of the one or more computing devices; before performing automated speech recognition on voice input from the one or more computing devices, selecting, by the computer system and based at least in part on the geographic location that is identified based at least in part on the search queries included in the search history, a first grammar from among a plurality of grammars, the first grammar including a vocabulary that is relevant to the geographic location that is identified based at least in part on the search queries included in the search history; and outputting, by the computer system, information that identifies the first grammar, wherein the outputted information causes a grammar used to analyze subsequently-received voice input from the one or more computing devices to be changed to the first grammar.