One or more computing devices may detect the presence of a user, determine default communication mode for communicating with the user, use the default communication mode to elicit a communicative gesture from the user, receive a signal identifying at least one communicative gesture from the user, and convert the identified communicative gestures into a command. The default communication mode may be based on the identity of the user. Alternatively, the default communication mode can be determined by using a first mode of communication to prompt the user to make a mode-selection gesture, and if a mode-selection gesture is detected from the user within a threshold period of time, setting the first mode of communication as the default communication mode. Otherwise, if no mode-selection gesture is detected within a threshold period of time, using an alternative mode of communication to prompt the user to make a mode-selection gesture.