Isan สู

← Ahom 𑜏𑜥 (cognate)

← Tai Dam ꪎꪴ (cognate)

← Lü ᦉᦴ (cognate)

← Lao ສູ (cognate)

← Northern Thai ᩈᩪ (cognate)

← Shan သူ (cognate)

← Proto-Southwestern Tai *suːᴬ (inherited)

← Tai Nüa ᥔᥧᥴ (cognate)

← Thai สู (cognate)

← Zhuang sou (cognate)

→ Shan သူ (cognate)

→ Tai Nüa ᥔᥧᥴ (cognate)

→ Thai สู (cognate)

→ Zhuang sou (cognate)