8. A method, comprising: receiving an output signal; receiving a qualifier signal indicating an occurrence of a trigger expression in the output signal; producing output audio at a speaker based, at least in part, on the output signal; receiving an input audio signal from a microphone, wherein the input audio signal represents user speech and at least a portion of the output audio; analyzing the input audio signal to detect an occurrence of the trigger expression in the input audio signal; and refraining from performing an action in response to speech that follows the occurrence of the trigger expression as represented by the input audio signal based, at least in part, on the qualifier signal indicating the occurrence of the trigger expression in the output signal.
8. A method, comprising: receiving an output signal; receiving a qualifier signal indicating an occurrence of a trigger expression in the output signal; producing output audio at a speaker based, at least in part, on the output signal; receiving an input audio signal from a microphone, wherein the input audio signal represents user speech and at least a portion of the output audio; analyzing the input audio signal to detect an occurrence of the trigger expression in the input audio signal; and refraining from performing an action in response to speech that follows the occurrence of the trigger expression as represented by the input audio signal based, at least in part, on the qualifier signal indicating the occurrence of the trigger expression in the output signal. 12. The method of claim 8 , wherein receiving the output signal comprises receiving a digital audio stream.