Techniques for implementing a “volatile” user ID are described. A system receives first input audio data and determines first speech processing results therefrom. The system also determines a first user that spoke an utterance represented in the first input audio data. The system establishes a multi-turn dialog session with a first content source and receives first output data from the first content source based on the first speech processing results and the first user. The system causes a device to present first output content associated with the first output data. The system then receives second input audio data and determines second speech processing results therefrom. The system also determines the second input audio data corresponds to the same multi-turn dialog session. The system determines a second user that spoke an utterance represented in the second input audio data and receives second output data from the first content source based on the second speech processing results and the second user. The system causes the device to present second output content associated with the second output data.