Cornish oy

← Breton vi (cognate)

← Proto-Celtic *āuyom (inherited)

← Welsh wy (cognate)

← Proto-Indo-European *h₂ōwyóm (inherited)

← Proto-Indo-European *h₂éwis (mention)

← Latin avis (cognate)

→ Breton vi (cognate)

→ Cornish oyow (suffix)