In addition to the national standard spoken language/dialect (Putonghua / Guoyu), every region and locality has its own native variants of spoken Chinese. The map below shows these subdivisions ("languages" or "dialect groups") within Chinese. The traditionally recognized seven main groups, in order of population size are:

Mandarin (Simplified Chinese: 官话 or 北方话; Traditional Chinese: 官話 or 北方話; Pinyin: běifānghuà or guānhuà), (c. 800 million), not to be confused with Putonghua / Guoyu, often also called "Mandarin", the official spoken language of China; 
Wu 吳/吴 , which includes Shanghainese, (c. 90 million) 
Cantonese 粵/粤, (c. 80 million) 
Min 閩/闽, which includes Taiwanese, (c. 50 million) 
Hakka 客家 or 客, (c. 35 million) 
Xiang 湘, (c. 35 million) 
Gan 贛/赣, (c. 31 million) 
Chinese linguists have recently distinguished 3 more groups from the traditional seven:

Jin 晉/晋 from Mandarin 
Hui 徽 from Wu 
Ping 平話/平话 partly from Cantonese 
There are also many smaller groups that are not yet classified, such as: Danzhou dialect, spoken in Danzhou, on Hainan Island; Xianghua (乡话), not to be confused with Xiang (湘), spoken in western Hunan; and Shaozhou Tuhua, spoken in northern Guangdong. The Dungan language, spoken in Central Asia, is very closely related to Mandarin. However, it is not generally considered "Chinese," because it is written in Cyrillic and spoken by people outside China who are not considered Chinese in any sense. See List of Chinese dialects for a comprehensive listing of individual dialects within these large, broad groupings.