The Sinitic languages, often synonymous with the Chinese languages, 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, whose classification is difficult, may be Sinitic; otherwise Sinitic is equivalent to the Chinese languages, and often used in opposition to "Chinese dialects" to convey the idea that these are distinct languages rather than dialects of a single language.
L1 speakers of Chinese languages and other Sino-Tibetan languages according to Ethnologue
Assuming Bai is Sinitic, it diverged at approximately the time of Old Chinese, perhaps before. By the time of Middle Chinese, the Min languages had also split off. An evidence is that all Chinese languages can be fit into the structure of Qieyun except Min. Languages traceable to Middle Chinese include Mandarin, Wu, Hakka, and Yue. As more comparative work is done, additional "dialects" are found to be mutually unintelligible with their parent language; the latest to be separated out as languages were Huizhou, Jin, Pinghua, and Qiongwen, though the remaining Wu and Yue varieties are not all mutually intelligible, or have very limited intelligibility. Some varieties remain unclassified within Chinese.