Old Irish tú

← Proto-Celtic *tū (inherited)

← Old Church Slavonic тꙑ (cognate)

← Welsh ti (cognate)

← Gothic 𐌸𐌿 (cognate)

← Ancient Greek σύ (cognate)

← Proto-Indo-European *túh₂ (inherited)

← Latin tū (cognate)

→ Irish tú (inherited)

→ Irish thú (inherited)

→ Scottish Gaelic thu (inherited)

→ Manx oo (inherited)

→ Old Irish tussu (affix)