Origin and history of yatter

"grumble, chatter aimlessly, nag," 1829, northern England dialect variant of gnatter "to chatter, grumble," earlier (18c.) "to nibble away," probably of echoic origin. Related: Nattered; nattering. As a noun, 1866, from the verb.

In the United States today, we have more than our share of the nattering nabobs of negativism. They have formed their own 4-H Club — the ‘hopeless, hysterical hypochondriacs of history.' [U.S. Vice President Spiro Agnew (in reference to the media), address to the California Republican state convention, Sept. 11, 1970 (the speech was written by then-White House speechwriter William Safire)]

"and so on," 1990s, of echoic origin (compare yatata "talk idly, chatter," 1940s; and yatter "to talk incessantly or idly," by 1825).