The major dialect families: what they share, where they differ, and how each sounds.
North, northeast & southwest China; the base of Standard Chinese
The largest group by far, roughly two-thirds of all Chinese speakers, from Harbin to Kunming. Standard Mandarin (普通话/国语) is built on its northern varieties. The grammar is remarkably uniform, but the sound ranges from the rolling 儿化 of the northeast to the soft, particle-rich speech of Sichuan and Yunnan.
Shanghai, southern Jiangsu, Zhejiang
Around 80 million speakers. Wu keeps the ancient voiced initials (浊音) that Mandarin lost, the source of its famous ‘soft’ sound, and runs on seven or eight tones. Suzhou speech was praised in poetry; Shanghainese is its best-known member. Not mutually intelligible with Mandarin.
Guangdong, Guangxi, Hong Kong, Macau, overseas Chinatowns
About 85 million speakers. Cantonese keeps the final consonants (-p/-t/-k/-m) and the six-to-nine-tone system Mandarin dropped, so Tang poetry often still rhymes in it. Hong Kong gives it a full written vernacular and a film-and-pop culture of its own.
Fujian, Taiwan, Hainan, Chaoshan; huge overseas diaspora
The most internally diverse branch: Hokkien (闽南话, including Taiwanese), Teochew, Fuzhounese and Hainanese are effectively separate languages. Min descends from Old Chinese rather than Middle Chinese, so its layers are older than Mandarin’s. Around 70 million speakers, with a vast overseas diaspora.
Scattered enclaves: Guangdong, Fujian, Jiangxi, Taiwan, diaspora
The speech of the Hakka ‘guest families’, who migrated across a dozen provinces over centuries and kept their tongue as a mark of identity, from Meizhou and Fujian to Taiwan, Malaysia and Mauritius. It preserves older final consonants and the entering tone, and says 食 rather than 吃 for ‘eat’.