This is one type of craft that would require the ventriloquist to “throw” his voice to make it appear like someone else is talking. The ventriloquist would need to change his voice so that the audience will know if it is the ventriloquist who is speaking or the puppet that he is holding. There is some history to ventriloquism though.
It started out as a religious practice that was done by the Greeks. It carried on until such time when people realized that this procedure may be dangerous so it was banned. Modern ventriloquism is known to be complicated and not everyone can do it. It may take years of practice before some ventriloquists can be good at what they do.