biloquial

adjective

Of, pertaining to, or possessing the ability to speak in two different voices, especially as a ventriloquist.

Deception was often unnecessarily practised, and my biloquial faculty did not lie unemployed . . . . Standing one evening on the steps of the great altar, this devout friar expatiated on the miraculous evidences of his religion; and, in a moment of enthusiasm, appealed to San Lorenzo, whose martyrdom was displayed before us. No sooner was the appeal made than the saint, obsequious to the summons, whispered his responses from the shrine.

See Also: biloquism, biloquist, biloquium