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 — from Beijing to Sichuan and Yunnan. Standard Mandarin (普通话/國語) is built on northern varieties; southern and southwestern varieties keep their own flavor (儿化 érhuà up north, lively sentence particles down south).
Shanghai, southern Jiangsu, Zhejiang
Home of Shanghainese and the soft Suzhou speech poets praised. Keeps the ancient voiced initials (浊音) Mandarin lost — its famous ‘soft’ sound. Mutually unintelligible with Mandarin.
Guangdong, Guangxi, Hong Kong, Macau, overseas Chinatowns
Cantonese keeps nine tone contours and final consonants (-p/-t/-k/-m) Mandarin dropped — Tang poetry rhymes still work in it. Written Cantonese is a literature of its own.
Fujian, Taiwan, Hainan, Chaoshan; huge overseas diaspora
The most internally diverse group — Hokkien (闽南话, incl. Taiwanese), Teochew, Fuzhounese and Hainanese are separate languages. Layers from Old Chinese, not Middle Chinese.
Scattered enclaves: Guangdong, Fujian, Jiangxi, Taiwan, diaspora
The speech of the Hakka ‘guest families’, migrants who kept their tongue across a dozen provinces. Preserves older forms; a marker of identity from Meizhou to Mauritius.