Green’s Dictionary of Slang

talking nonsense, babbling on.

1910		‘Doss Chiderdoss’ ‘A Dramatic Forecast’ Sporting Times 31 Dec. 2/2: [I] hoped someone would put the bluff fool in a cage / Ere his blitherings caused me to shunt.
1910–38		in G. Legman Limerick (1953) 105: What’s all this blithering about?