I haven't had a Paul Winchell clip up here for a while. When I was a kid, Paul Winchell was a huge hero of mine and I still think he was the best ventriloquist of all time. This isn't the funniest sketch he ever did but it's a terrific example of how good he was at making you forget that he was doing both voices in a scene. There's one part of this where he's doing his own voice and Jerry's and Knucklehead's, switching off with the greatest of ease…and the end song is especially delightful. I'm not sure what year this was but it looks to be around 1956 or '57 and I think it was done live.
Anyway, the thing to note is that ventriloquism is an art of misdirection. It's as much in the acting as in the lip control…and while Paul didn't move his, what makes the illusion work is how he changes voices and attitudes and how he times it so expertly. Also note how Knucklehead doesn't seem nearly as convincing as Jerry in this…because Knuck was being operated by someone other than Paul and voice wasn't perfectly in sync with the manipulation. This is really a great example of a master at work…