Why does inner speech sound like a voice when no sound is heard? · Grey Matter

When people speak, the motor areas send a copy of each command to the auditory cortex, which predicts the sound about to be heard so that one's own voice can be told apart from someone else's.

Why does inner speech sound like a voice when no sound is heard?

When people speak, the motor areas send a copy of each command to the auditory cortex, which predicts the sound about to be heard so that one's own voice can be told apart from someone else's. In inner speech the command is prepared and the copy is sent, but the mouth never moves, so the auditory cortex is left with the prediction alone. Recordings of imagined speech show auditory activity following the motor planning by a fraction of a second, which is a plausible origin for the heard quality of the inner voice.