The Canary Murder Case" was not William Powell's first talking film. That was "Interference", also by Paramount. Also, even though Louise Brooks was prominently advertised as "The Canary", a showgirl determined to marry a rich young man just for the fun of ruining him, she doesn't get much screen time. That is because The Canary Murder Case was originally shot as a silent film, but then it was decided to make it into a talking picture. Louise Brooks detested talking pictures and refused to stay and reshoot her part. This pretty much finished her in film in the U.S., although she went to Germany and did some of her finest work. Unfortunately, that fact was not discovered in this country for another thirty years. Instead of starting over with another actress, it was decided to have someone dub Louise' voice, and as a result her lip movement is noticeably out of synchronization with her "voice". Much of The Canary's speaking is done with her back to the camera, minimizing the problem.
William Powell, who was quite wooden in his first talking performance in "Interference", does much better here. You see him moving toward the characterization of the dapper P.I. that he played through the Thin Man series of films beginning in 1934. Powell had a pretty good silent career after a long period of poverty doing stage work prior to 1920, and he was one of the few silent stars to successfully make the transition to talking films.