Bouyei sis

← Ahom 𑜏𑜣 (cognate)

← Tai Dam ꪎꪲ꪿ (cognate)

← Lü ᦉᦲᧈ (cognate)

← Lao ສີ່ (cognate)

← Northern Thai ᩈᩦ᩵ (cognate)

← Shan သီႇ (cognate)

← Proto-Sino-Tibetan *b-ləj (derived)

← Proto-Tai *siːᴮ (inherited)

← Tai Nüa ᥔᥤᥱ (cognate)

← Thai สี่ (cognate)

← Zhuang seiq (cognate)

→ Tai Dam ꪎꪲ꪿ (cognate)

→ Lü ᦉᦲᧈ (cognate)

→ Lao ສີ່ (cognate)

→ Shan သီႇ (cognate)

→ Tai Nüa ᥔᥤᥱ (cognate)

→ Thai สี่ (cognate)

→ Zhuang seiq (cognate)