jibber-jabber (v.) Look up jibber-jabber at Dictionary.com
1728, "to talk gibberish," reduplication of jabber (q.v.). Related: Jibber-jabbering. As a noun from 1813, also gibber-gabber. Compare gibble-gabble "idle talk, chatter" (c. 1600). Jibber (v.) is attested from 1824.