In *BlacKkKlansman* (2018), after the opening scene of [*Gone with the Wind*][1], Dr. Kennebrew Beauregard appeared on the screen and gave a speech:

> Is the final nail in a black coffin towards America becoming a mongrel
> nation. We had a great way of life. We had...**Ma-ma-ma-ma-ma!** We had a
> great way of life.

Why does Dr. Kennebrew Beauregard utter gibberish in the middle of his speech?

  [1]: https://movies.stackexchange.com/questions/92066/what-is-the-significance-of-the-opening-scene-of-blackkklansman