The Sinitic languages, often synonymous with the group of Chinese varieties, are a family of Sino-Tibetan languages. They have frequently been postulated to constitute a primary branch, but this is rejected by an increasing number of researchers. The Bai languages and possible relatives, whose classification is difficult, may also be Sinitic; otherwise Sinitic is equivalent to Chinese, and the term may be used to indicate that the varieties of Chinese are distinct languages rather than dialects of a single language.