There are hundreds of local Chinese language varieties forming a branch of the Sino-Tibetan language family, many of which are not mutually intelligible. Variation is particularly strong in the more mountainous southeast part of mainland China. The varieties are typically classified into several groups: Mandarin, Wu, Min, Xiang, Gan, Jin, Hakka and Yue, though some varieties remain unclassified. These groups are neither clades nor individual languages defined by mutual intelligibility, but reflect common phonological developments from Middle Chinese.
Chinese varieties have the greatest differences in their phonology, and to a lesser extent in vocabulary and syntax. Southern varieties tend to have fewer initial consonants than northern and central varieties, but more often preserve the Middle Chinese final consonants. All have phonemic tones, with northern varieties tending to have fewer distinctions than southern ones. Many have tone sandhi, with the most complex patterns in the coastal area from Zhejiang to eastern Guangdong.
