Green’s Dictionary of Slang

to talk, to chatter; thus gabbering, verbose; gabbery, foolish chatter.

a.1661		‘The Rebellion’ Rump Poems and Songs (1662) I 292: Nay, then let’s have none, sayes gabbering Jone.
1725		N. Ward Amorous Bugbears 19: When a medley of all Nations are gabbering together with Confusion in their Countenances.
1916		Hull Dly Mail 10 Jan. 2/5: All the natives stare and gabber at you in their own language.
1922		Joyce Ulysses 714: What do they find to gabber about all night.
1930		Hull Dly Mail 22 Aug. 1/6: When his wife commenced to ‘gabber’ he had funny noises in his head which sent him nearly ‘potty’.
1984		M. Stott Aliens over Antipodes 41: When they spotted Mr Lithbridge they began gabbering excitedly to each other in a foreign language.