If you want a little historical perspective you're home.
“In the ’20s, you were a face. And that was enough. In the ’30s, you also had to be a voice. And your voice had to match your face, if you can imagine that. Jimmy Cagney and Eddie Robinson had voices that were as important as the characters they played.” Joan Blondell
Not a very good movie, one immortal line, “Mmm, that dirty, double-crossin’ rat!”
However, the art work for this lobby card is worth taking a look at:
And, as mentioned by Mr. Kaplan in the comments, perhaps acting in pre-code Hollywood required a bit of legwork as well.