37. The computer-readable medium of claim 27 , the operations comprising: determining, by the first computing device, one or more speaker models that are each stored on the first computing device and for a person other than a user of the first computing device, wherein determining to remain in the locked state and not respond to the voice command comprises determining, by the first computing device, to remain in the locked state and not respond to the voice command despite receiving the audio data that corresponds to the utterance of the voice command that is preceded by the particular, predefined hotword using the one or more speaker models that are each stored on the first computing device and for a person other than the user of the first computing device.
39. The computer-readable medium of claim 37 , the operations comprising: determining, by the first computing device for a third computing device, a frequency with which the third computing device is located in a physical area near a physical location of the first computing device; determining, by the first computing device, whether the frequency satisfies a threshold frequency; and associating, by the first computing device, a particular speaker model specific to a particular user of the third computing device with the first computing device in response to determining that the frequency satisfies the threshold frequency.