талдычить

Etymology
From dialectal, as also , , , for now standard , 🇨🇬, ,. In dialects also, , ,. And he who holds the sermons is called, , which can be deemed the origin of the verb, derived from or  (an uncommon variant of the former seen in  reanalyzed on pre-Slavic ū-stems), then for the verb.

Verb

 * 1)  to go on and on, to harp on