10. The computer-implemented method of claim 6 , wherein the geographic location is identified from the content based on the geographic location occurring in the content at least a threshold number of times.
6. A computer-implemented method comprising: accessing, by a computer system, information that identifies content that was previously requested by and displayed on a mobile computing device that is associated with a user, wherein the content comprises one or more web pages that were previously displayed on the mobile computing device; identifying, based at least in part on the content that was previously requested and displayed on the mobile computing device, a geographic location to which future voice input from the user is likely to relate; selecting, by the computer system and based at least in part on the identified geographic location, a first grammar from among a plurality of grammars, wherein the first grammar includes a vocabulary that is relevant to the geographic location; and outputting, by the computer system, information that identifies the first grammar, wherein the outputted information causes a grammar used to analyze voice input from the mobile computing device to be changed to the first grammar.