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.
1823, "frill of a men's shirt," from French jabot "gizzard (of a bird), frill on a shirt front" (16c.), a word of unknown origin. Klein suggests a connection with gaver "to cram, gorge," and thus ultimately with English jaw (n.). Of women's clothing from 1869.