←
Proto-Indo-Iranian *šwáćš (inherited)
←
Proto-Indo-European *swéḱs (inherited)
←
Proto-Iranian *šwáš (inherited)
←
Northern Kurdish şeş (cognate)
←
Lithuanian šeši (cognate)
←
Middle Persian (inherited)
←
Middle Persian swš (derived)
←
Russian шесть (cognate)
→
Central Kurdish شەش (cognate)
→
Northern Kurdish şeş (cognate)