Where does “Borbora” come from?

Borbora (Lower Sorbian) comes from Latin barbara, from Latin barbarus, from Ancient Greek βάρβαρος, from Proto-Indo-European balb-.

Ancestry of “Borbora”, step by step

Step	Language	Word	Meaning
1	Latin	barbara	a wild, savage, cruel, barbarous, shameless, or...
2	Latin	barbarus	foreign; savage; uncivilized
3	Ancient Greek	βάρβαρος	non-Greek-speaking, foreign; barbaric, brutal,...
4	Proto-Indo-European	balb-	—