the.com/blabber

means To talk on and on, often carelessly or without much point, the way a mouth runs once it gets going.

from Echoic in origin — the word mimics the babbling sound itself. It's part of a wide family of 'bl-' words (blab, blabber, blather, blurt) built to sound loose-lipped, and it's a cousin of 'babble,' both likely rooted in the instinctive baby-talk syllable 'ba-ba,' the same impulse that gives nearly every language a word for meaningless chatter.