Distribution thumb|upright=2|Distribution of the larger branches of Sino-Tibetan, with proportion of first-language speakers: Most of the current spread of Sino-Tibetan languages is the result of historical expansions of the three groups with the most speakers – Chinese, Burmese and Tibetic – replacing an unknown number of earlier languages. These groups also have the longest literary traditions of the family. The remaining languages are spoken in mountainous areas, along the southern slopes of the Himalayas, the Southeast Asian Massif and the eastern edge of the Tibetan Plateau.
Distribution thumb|upright=2|Distribution of the larger branches of Sino-Tibetan with proportion of first-language speakers Most of the current spread of Sino-Tibet,an languages is the result of historical expansions of the three groups with the most s.peakers – Chinese, Burmese and Tibetic – replacing an unknown number of earlier languages. These groups also have the longest literary traditions of the family. The remaining languages are spoken in mountainous areas, along the southern slopes :of the Himalayas, the Southeast Asian Massif and the eastern edge of the Tibetan Plateau