Ventriloquy: The act, art or practice of speaking in such a manner that the voice appears to come not from the person, but from some distant place.

Ventriloquy comes from the Latin word ventriloquus which itself comes from two other Latin words. Venter means stomach or belly.  And loqui means to speak.  So, a ventriloquist is someone who appears to be speaking, not with the mouth, but with, perhaps, the stomach.

The ancients believed that a person practicing ventriloquy was under duress, or under the spell of a demonic power, or the power of a deity.