gibber

Whether gibber comes from geber, as Dr Johnson contends, must remain in doubt.

Gibberish is no doubt derived from gibber, and it means idle nonsense.

See those things that ape our species dance and gibber round the famishing, hunted wretch.

Never a word they said, never a sound from the mouths that seemed to gibber.

If it had not been for the generous supply of "days off" that the Skipper allowed us, we should by February have begun to gibber.