Old Irish sine

← Proto-Celtic *sɸenyos (inherited)

← Proto-Indo-European *pstḗn (derived)

→ Irish sine (inherited)

→ Scottish Gaelic sine (inherited)

→ Scottish Gaelic sine (inherited)

→ Manx sheeiney (derived)

→ Old Irish céilsine (suffix)

→ Old Irish coicéilsine (suffix)

→ Old Irish fáithsine (suffix)