Where does “болта́ть” come from?

болта́ть (Russian) comes from Proto-Slavic bьltati, from Proto-Indo-European bʰel-, from Proto-Indo-European bʰōl-.

Ancestry of “болта́ть”, step by step

Step	Language	Word	Meaning
1	Proto-Slavic	bьltati	to mix, stir; to babble
2	Proto-Indo-European	bʰel-	to sound; to speak, roar, bark; shiny, white; to...
3	Proto-Indo-European	bʰōl-	—

болта́ть — Etymology, Origin & Word History | Etymology Explorer