Speech which combines English (or some other language) and native-sounding gibberish for humorous effect.
Doublespeak.
Lies, especially in a formal political statement.
A situation when two people talk at the same time, causing overlapping audio signals.
A simple phonetic code with a regular infix that makes meaningful speech sound unintelligible.
Speech which is undecipherable to the listener because it is in a language he or she does not understand; mumbo jumbo.
Background noise of simultaneous conversations, none of which is decipherable since the actors are repeating the word rhubarb or other words with similar attributes.
Blah blah; etc, etc.