ventrilocution

— "You are not apprized of the existence of a power which I possess. I know not by what name to call it. [* Biloquium, or ventrilocution. Sound is varied according to the variations of direction and distance. . . .] It enables me to mimic exactly the voice of another, and to modify the sound so that it shall appear to come from what quarter, and be uttered at what distance I please."