American silent film comedies were dominated by sight gags, stunts and comic violence. With the advent of sound, comedies in the 1930s were a riot of runaway heiresses and fast-talking screwballs. It was more than a technological pivot--the first feature-length sound film, The Jazz Singer (1927), changed Hollywood. Lost in the discussion of that transition is the overlap between the two genres. Charlie Chaplin, Buster Keaton and...