Is said to be the Black Lodge, where many keys of black magic are working, including ventriloquism and necromancy.
So ventriloquism is not necessarily tied to necromancy, though I can see the application. When a person dies, there may be trapped air or gas, which when coming through the throat, striking the vocal cords making them seem to talk. When I drove for a mortuary company, one seemed to talk while I was driving to a funeral home, scaring the crap out of me.
So there’s that. Statues that talked were a result of ventriloquism?