Where does “bravus” come from?

bravus (Medieval Latin) comes from Latin barbarus, from Ancient Greek βάρβαρος, from Proto-Indo-European balb-.

Ancestry of “bravus”, step by step

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