Welsh brwydr

← Proto-Celtic *brētrā (inherited)

← Proto-Celtic *brē- (mention)

← Proto-Celtic *bri- (mention)

← Proto-Indo-European *bʰerH- (derived)

← Old Irish bríathar (cognate)

← Middle Welsh brwydyr (inherited)

→ Welsh brwydro (affix)

→ Old Irish bríathar (cognate)

→ Albanian brit (cognate)