Pretty girl asked me, why I write mumbo- jumbo - - to which I replied, "my dear, it happens to be gobble-dy-****..."
Gibberish, alternatively jibberish, jibber, jibber-jabber, or gobbledygook, is language that is (or appears to be) nonsense. It may include speech sounds that are not actual words, or language games and specialized jargon that seems nonsensical to outsiders.