Is there a reason why they made made up silly languages?
I'm thinking to save budget, for I have seen a few movies from this 30s era, where they do this. It's very silly.
"You know, my name..."
Constructed languages have been popular for a long time and continue to be. One advantage I can see for using them in movies is that it's easy to train the actors to speak. If they flub then so what, that flub becomes part of the language. If they are trying to speak in Swedish or Swahili they would be both trying to pull off speaking in a tongue unknown to them but also with the correct pronunciation, pacing, phrasing, etc.
In written works I suspect constructed languages are more of an intellectual challenge for the author. For example, J. R. R. Tolkien's Westron which was spoken in Middle-earth plus Tolkien's Quenya and Sindarin were all fun for him.