31. The computer-readable medium of claim 27 , wherein transmitting the message to the second computing device comprises transmitting, by the first computing device, the message to the second computing device using a short-range communication protocol.
27. A non-transitory computer-readable medium storing software comprising instructions executable by one or more computers which, upon such execution, cause the one or more computers to perform operations comprising: obtaining, by a first computing device that is configured to respond to voice commands while in a locked state upon receipt of a particular, predefined hotword, a value for a setting that indicates that the first computing device is permitted to provide speaker verification data to other computing devices; receiving, by the first computing device, audio data that corresponds to an utterance of a voice command that is preceded by the particular, predefined hotword, the audio data being received while the first computing device is in a locked state and is co-located with a second computing device that is also configured to respond to voice commands that are preceded by the particular, predefined hotword; while the first computing device is in the locked state, and based on the obtained value for the setting that indicates that the first computing device is permitted to share speaker verification data with other computing devices, transmitting, by the first computing device, a message to the second computing device that (i) is co-located with the first computing device and (ii) is configured to respond to voice commands that are preceded by the particular, predefined hotword; and 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.