Welsh ais

← Proto-Brythonic *assī (inherited)

← Proto-Celtic *astū (inherited)

← Welsh asen (doublet)

← Welsh asgwrn (mention)

← Irish easna (cognate)

← Proto-Indo-European (mention)

← Proto-Indo-European *h₃ésth₁ (inherited)

← Latin os (cognate)

← Albanian asht (cognate)

← Middle Welsh eis (inherited)

→ Welsh asgwrn (mention)

→ Welsh asen (doublet)

→ Irish easna (cognate)