16. A computer-readable storage device encoded with instructions that, when executed, cause at least one processor of a first computing device to: determine a context of the first computing device, the context including an indication that a second computing device is proximate to the first computing device; determine, based at least in part on the context, a subset of contextual audio triggers from a plurality of contextual audio triggers, each contextual audio trigger from the plurality of contextual audio triggers usable to initiate interaction with the first computing device, wherein each contextual audio trigger from the subset of contextual audio triggers is associated with a respective operation of the first computing device and with the context of the first computing device, and wherein one of the subset of contextual audio triggers is associated with a first operation to cause the second computing device to perform a second operation; receive audio data; and responsive to determining that a portion of the audio data corresponds to a particular contextual audio trigger from the subset of contextual audio triggers, perform the respective operation associated with the particular contextual audio trigger.
16. A computer-readable storage device encoded with instructions that, when executed, cause at least one processor of a first computing device to: determine a context of the first computing device, the context including an indication that a second computing device is proximate to the first computing device; determine, based at least in part on the context, a subset of contextual audio triggers from a plurality of contextual audio triggers, each contextual audio trigger from the plurality of contextual audio triggers usable to initiate interaction with the first computing device, wherein each contextual audio trigger from the subset of contextual audio triggers is associated with a respective operation of the first computing device and with the context of the first computing device, and wherein one of the subset of contextual audio triggers is associated with a first operation to cause the second computing device to perform a second operation; receive audio data; and responsive to determining that a portion of the audio data corresponds to a particular contextual audio trigger from the subset of contextual audio triggers, perform the respective operation associated with the particular contextual audio trigger. 18. The computer-readable storage device of claim 16 , wherein the instructions that cause the at least one processor to determine the subset of contextual audio triggers comprise instructions that cause the at least one processor to determine the subset of contextual audio triggers based at least in part on a frequency with which the plurality of contextual audio triggers were previously used in the context.