ventriloquism

n. (also ventriloquy) skill of speaking without moving the lips, esp. As entertainment with a dummy.  ventriloquist n. [latin venter belly, loquor speak]

n. The act, art, or practice of speaking in such a manner that the voice appears to come, not from the person speaking, but from some other source, as from the opposite side of the room, from the cellar, etc.