18. The non-transitory computer readable medium of claim 17 , wherein the functions further comprise: deactivating the trigger word detection subroutine in response to determining that the mobile computing device is receiving operating power from the internal battery source.
17. A non-transitory computer readable medium having stored therein executable instructions that, when executed by a computing device having at least one processor, causes the computing device to perform functions comprising: determining whether a mobile computing device is receiving operating power from either an external power source or an internal battery source; and activating a trigger word detection subroutine in response to determining that the mobile computing device is receiving power from the external power source, wherein the trigger word detection subroutine comprises continually determining whether spoken input received via a microphone includes one or more trigger words associated with a voice command prompt application and, in response to determining that the spoken input includes the one or more trigger words associated with the voice command prompt application, launching the voice command prompt application, wherein the voice command prompt application is configured to receive via the microphone additional spoken input that causes the mobile computing device to launch one or more other applications, and wherein launching the voice command prompt application comprises displaying a voice command prompt on the mobile computing device.