A raucous sounding fart. Usually created by lifting one leg to get the best sound. In 1977 this was also known as a "Jubilee" Jabble in honour of HM The Queen's 25th year on the British throne.
Jibber jabber is Incoherent and unintelligible rapid speech often in slang or patois. Used in the UK as a disparaging name for other languages such as French, Spanish or American.
“It was all jibber jabber. Couldn’t understand a dam’ word the wretched feller was sayin’, Jeeves.”
“But, Milord, he was an American.”
“Yes?”