grammelot

noun1

1. •
   A style of language used in satirical theater: a gibberish with macaronic and onomatopoeic elements, used in association with mime and mimicry.

   • Actually, much of “Mistero Buffo” doesn't require translation and indeed is untranslatable: Mr. Fo speaks in “grammelot,” a kind of polyglot gabble speckled with an occasional intelligible word. — 1986