Welsh blwydd

← Breton blizenn (cognate)

← Breton bloaz (cognate)

← Proto-Celtic *blēdanī (inherited)

← Welsh blynedd (cognate)

← Proto-West Germanic *blait (cognate)

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

← Cornish bledhen (cognate)

← Cornish bloth (cognate)

← Lithuanian blaĩvas (cognate)

← Old Breton blened (cognate)

← Old Welsh bloidin (inherited)

← Old Irish blíadain (cognate)

← Albanian blehurë (cognate)

← Middle Welsh blwyddyn (inherited)

→ Breton bloaz (cognate)

→ Welsh blwyddyn (cognate)

→ Welsh blwyddiadur (suffix)

→ Welsh pen-blwydd (affix)

→ Welsh blynedd (mention)

→ Welsh dwyflwydd (compound)

→ Cornish bledhen (cognate)