1. A computer-implemented method, comprising: receiving, by a computing system, an input that was entered at a mobile computing device; identifying, by the computing system, the input as being ambiguous due to the input being able to be represented by either of at least two commands or at least two transcriptions of audio; determining, by the computing system, whether the mobile computing device is identified as traveling in a vehicle, wherein the computing system determines that the mobile computing device is identified as traveling in the vehicle based on a determination that the mobile computing device is traveling at a rate of speed that exceeds a threshold value using measurements by one or more sensors in the mobile computing device; applying, by the computing system, the input to a rule that uses the determination that the mobile computing device is identified as traveling in the vehicle to select one of the at least two commands or the at least two transcriptions of audio as a selected command or transcription; and causing, by the computing system, the mobile computing device to provide output associated with the selected command or transcription.