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?”
What's poppin Jimbo, is a meme that originated from Jimmy newtron the kids TV show, when Jimmy newtron's dad asks him like ''how's you're day?'' But instead says''What's poppin Jimbo?''. This meme is usually used when, you call to one of you're friends, then they say, ''What's poppin Jimbo?''