I think 4dn works if you take ‘tongue’ as a verb.

Re 26ac: HAVERING = ‘vacillation’: I can just hear my Scottish husband exclaiming, ‘Havers!’ [Nonsense!']. I’ve heard that so many times that I’m particularly interested in this word. My [rather old] SOED has only ‘Scottish and Northern dialect: to talk foolishly, to talk nonsense’, while Collins has ‘dither’ as the second definition, after ‘babble’.

My own theory is that we English confuse this word with ‘waver’ [plus perhaps even 'hover'], which Chambers gives as the second definition, after ‘talk nonsense’, having accepted it through usage.

I’m not meaning to be contentious – just interested in the way language develops!