Where does “بَرْبَر” come from?

بَرْبَر (Arabic) comes from Ancient Greek βάρβαρος, from Proto-Indo-European balb-.

Ancestry of “بَرْبَر”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	βάρβαρος	non-Greek-speaking, foreign; barbaric, brutal,...
2	Proto-Indo-European	balb-	—