Green’s Dictionary of Slang

to talk in a pleasant manner.

1885		Bulletin (Sydney) 18 Apr. 9/3: Young Cogill warbles while the other twists and turns till he resembles some uncanny thing that men see after a full supper of tinned lobster. All this time he is ‘footing’ a measure as grotesque as the wildest pirouette made by the ‘cutty sark’ in the auld roadside kirk.
1902		Knaresborough Post 25 Jan. 2/2: Here is a stick of Dr Windgall’s medicated candy [...] You get up behind the counter and begin to warble your little warb’.
1907		C.E. Mulford Bar-20 xi: If yu needs any referee or a side pardner in any ruction yu has only got to warble up my way.
1934		Film Fun 8 Sept. 24: ‘What-ho!’ he warbled.
1989		T. Blacker Fixx 24: Mother would warble on about her hatchet-faced forbears.
2001		N. Barlay Hooky Gear 167: Amazin how fear clear up Arnos windpipe an get him warblin like a movie star.