V entriloquism, according to Wikipedia, was originally a religious practice. The name comes from the Latin word which means ‘to speak from the stomach', ( venter (belly) and loqui (speak)).
The Greeks called this gastromancy. The noises produced by the stomach were thought to be the voices of the un-living, who took up residence in the stomach of the ventriloquist, who was believed to communicate with the dead and foretell the future!
One of the earliest recorded group of prophets to utilise this technique was the Pythia, the priestess at the temple of Apollo in Delphi, who acted as the conduit for the Delphic Oracle. In the Middle Ages, it was thought to be similar to witchcraft.
As spiritualism led to stage magic and escapology, ventriloquism became more of a performance art and around the 19th century, it shed its mystical trappings. Zulus, Eskimo and Maori also have a tradition of ventriloquism for ritual or religious purposes.