Be-Tai languages

┗ Tai languages

　┗ Southwestern Tai languages

　　┣ Chiang Saen languages

　　┃: Thai language, Tai Lue language

　　┃

　　┣ Lao-Phuta languages

　　┃: Lao language, Isan language

　　┃

　　┗ Northwestern

　　　: Tai Nuea language

Kam–Sui languages

: Kam language, Sui language