13. The device of claim 4 , wherein at least one of the profile building component or the speech recognition component is further configured to: perform speech recognition on the first voice signal to obtain speech recognition results; determine event information from the speech recognition results, wherein the event information includes date information; and provide a reminder to the user concerning the event using the date information.
4. A device comprising: a profile building component in communication with an electronic data store; a sensor configured to detect presence of a user independent of a direction of the user's gaze and without detecting physical contact between the user and the device; and a speech recognition component; wherein the profile building component is configured to: receive, from the sensor, an indication that presence of the user was detected; begin to listen for utterances from the user in response to receiving the indication; receive a first voice signal corresponding to a first utterance of a user; determine an identity of the user using the first voice signal; process the first voice signal to determine user information and a word sequence that indicates that a second utterance corresponding to a language characteristic is likely to be uttered by a second user different than the user at a time after a current time; store the user information in a user profile associated with the identity of the user; and select a second user acoustic model corresponding to the language characteristic for performing speech recognition.