Yvette sounds like a car? Like a Corvette or a Chevette?
I think Yvonne is much prettier. Yvette wears too much makeup, her skirt is too short, she smacks her gum and chain-smokes at the same time, and her fingernails are so long she is always breaking them and acting helpless and making somebody else do things for her.
Yvonne has a low, cool voice, her clothes are expensive and tasteful, she drives a beautiful, well-maintained older car, she smells good, and she can set tiles, play the piano, clean a fish and make a souffle with equal ease.