Jerry Lewis got his start in show business doing what was known as a "record act"--comically lip-synching to a phonograph record. He does a portion of it during the "serenade" sequence.
Me and my big mouth. I'd get rid of it, except it's such a handy place to keep my teeth.
Even though the story is supposedly taking place in the early 1930s, before the repeal of prohibition (1933), all the automobiles are of the late 1930s/early 1940s variety. All the women's hair styles and fashions are from 1953.