variety of Chinese dialects spoken in Shanghai, in southeastern Jiangsu province, and in Zhejiang province by more than 8 percent of the population of China (some 85 million people) at the turn of the 21st century. Major cities in which Wu is spoken include Hangzhou, Shanghai, Suzhou, Ningpo, and Wenzhou.

The Wu language originally spread from Suzhou, a cultural centre since the 5th century BC, and gained great importance at least as early as the period of the Ming dynasty (1368–1644), when Shanghai became an important metropolitan area. Wu differs from Modern Standard Chinese in preserving the initial voiced stops (sounds formed with complete closure in the vocal tract) and in using seven or eight tones to distinguish meanings between words or word elements that have the same series of consonants and vowels. (Modern Standard Chinese uses only four tones for such a purpose.) Like Modern Standard Chinese and the Mandarin language of northern China, the Wu language has lost most of the Ancient Chinese final consonants.