System and method of detecting a user's voice activity using an accelerometer

A mobile device detecting a user's voice activity comprising:

• an accelerometer to detect vibration of the user's vocal chords modulated by the user's vocal tract based on vibrations in bones and tissue of the user's head, wherein the accelerometer is included in an earphone portion of the mobile device;
• a voice activity detector (VAD) coupled to the accelerometer, the VAD to generate a VAD output based on (i) acoustic signals received from microphones included in the mobile device and (ii) data output by the accelerometer, wherein the VAD generates the VAD output by:
• detecting speech included in the acoustic signals,
• detecting the vibrations of the user's vocal chords from the data output by the accelerometer,
• computing the coincidence of the detected speech in acoustic signals and the vibrations of the user's vocal chords, and
• setting the VAD output to indicate that the user's voiced speech is detected if the coincidence is detected and setting the VAD output to indicate that the user's voiced speech is not detected if the coincidence is not detected;
• and
• a noise suppressor coupled to the microphones and the VAD, the noise suppressor to suppress noise from the acoustic signals from the microphones based on the VAD output.