6. A computer-implemented method comprising: under control of one or more computing devices configured with specific computer-executable instructions, transmitting, to a client device: an audio presentation comprising a first portion and a second portion, wherein the first portion corresponds to a first item and the second portion corresponds to a second item; a first marker corresponding to the first item; and a second marker corresponding to the second item; receiving, from the client device: audio data comprising a user utterance; and marker data comprising the first marker or the second marker; and selecting an item based at least on the marker data or the audio data, wherein the selected item comprises the first item or the second item.
6. A computer-implemented method comprising: under control of one or more computing devices configured with specific computer-executable instructions, transmitting, to a client device: an audio presentation comprising a first portion and a second portion, wherein the first portion corresponds to a first item and the second portion corresponds to a second item; a first marker corresponding to the first item; and a second marker corresponding to the second item; receiving, from the client device: audio data comprising a user utterance; and marker data comprising the first marker or the second marker; and selecting an item based at least on the marker data or the audio data, wherein the selected item comprises the first item or the second item. 10. The computer-implemented method of claim 6 , wherein the marker data further comprises a first presentation identifier corresponding to the audio presentation and a second presentation identifier corresponding to a second audio presentation being presented on the client device when the user utterance was initiated.