This research aims to compare languages and cultures of selected ethnic groups. It focuses on the linguistic and cultural transmission as well as adaptation of ethnic groups residing in Thailand, Lao PDR, Socialist Republic of Vietnam, and Republic of the Union of Myanmar resulting in a regional variation of ethnic languages and cultures. Black Tai and Tai Yuan were selected as a case study together with other related ethnic groups. The comparison of Black Tai and Tai Yuan languages focusses on tones as well as word and discourse. The cultural comparison deals with Black Tai music. This research is qualitative. It promotes the maintenance of ethnic groups and shared awareness of ethnic languages and cultures.