Wu (simplified Chinese: 吴语; traditional Chinese: 吳語; pinyin: Wúyǔ; Wugniu and IPA:6wu-gniu6 [ɦu˩.nʲy˦] (Shanghainese), 2ghou-gniu6 [ɦou˨.nʲy˧] (Suzhounese)) is a major group of Sinitic languages spoken primarily in Shanghai, Zhejiang province, and parts of Jiangsu province, especially south of the Yangtze River,[2] which makes up the cultural region of Wu.

[4] The Wu languages typically preserve all voiced initials of medieval Chinese, as well as the checked tone in the form of a glottal stop.

It is also of note that the influential linguist Chao Yuen Ren was a native speaker of Changzhounese, a variety of Northern Wu.

Affixing 閒話 is also common, and more typical of Northern Wu, as in 嘉興閒話 (Wugniu: ka-shin ghae-o) for the Jiaxing variety [zh].

After the migrations preceding the Upheaval of the Five Barbarians, the vernacular that would later lead to modern Wu Chinese started taking shape, though the court language of Jiankang (today Nanjing) was still noticeably different to that of the commonfolk.

The language slowly receded from the north due to growing pressure from the Central Plains, until its northern limit was set near the Yangtze River towards the end of the Western Jin dynasty.

A study of the variety spoken in Maqiao, a suburb of Shanghai, found that 126 out of around a thousand lexical items surveyed were of Kra-Dai origin.

[20] Shared terms with Austroasiatic languages have also been suggested, though many of them, such as Vietnamese đầm, bèo, and kè, have also been argued to be areal features, Chinese words in disguise, or long shots.

Due to events such as the Wu Hu uprising and the Disaster of Yongjia during the Western Jin dynasty, collectively known as the Upheaval of the Five Barbarians, the imperial court from the Heluo region, along with a large migration wave from the North that lasted 150 years,[24] primarily northern Jiangsu and much of Shandong, entered the Jiangnan region, establishing a new capital at Jiankang, modern-day Nanjing.

[25] Migrants went as far south as central Zhejiang,[24] though many settled in the geographically less challenging areas in the north, that is to say, the Yangtze Delta and the Hangjiahu Plain.

[15] This linguistic situation eventually led to the formation of modern Wu, with many early coincidental strata that are hard to differentiate today.

[33] It is also noted in the preface of the Qieyun, a Sui dynasty rime dictionary, that the speech of Wu, as well as that of Chu, is "at times too soft and light".

[35] After the An Lushan rebellion, significant migration into the northern Wu-speaking areas occurred, which some believe created the north-south geographical divide we see today.

[40] This also coincided with a large migration wave mostly from the Heluo region, a strip of the Central Plains south of the Yellow River that roughly stretches from Luoyang to Kaifeng,[41] which also brought a language that was not only phonologically and lexically different to the Wu Chinese of the time,[4] but was syntactically and morphologically distinct as well.

[42] Unlike the previous periods, the history of Wu Chinese after the Mongol conquest of China becomes a lot clearer, due to the emergence of vernacular texts.

[48] Dialectal differences were not as obvious in textual sources until Ming times,[49] and thus regional linguistic distinctions were only seen in media after the fall of the Yuan.

These differences are largely found in musical sources such as historical folk songs and tanci (a kind of ballad or lyric poem).

[59] From the late Qing period to Republican China (the 19th and early 20th centuries), long-form vernacular novels (蘇白小說 or 吳語小說) such as The Sing-song Girls of Shanghai (海上花列傳) and The Nine-tailed Turtle (九尾龜) started appearing.

[67] Several important proponents of vernacular Chinese in official use, such as Lu Xun and Chao Yuen Ren, were speakers of Northern Wu varieties, in this case Shaoxingese and Changzhounese respectively.

[69] After the founding of the People's Republic of China, the strong promotion of Mandarin in the Wu-speaking region yet again influenced the development of Wu Chinese.

Its original classification, along with the other Sinitic varieties, was established in 1937 by Li Fang-Kuei, whose boundaries more or less have remained the same,[5] and were adopted by Yuan Jiahua in his influential 1961 dialect primer.

The Taihu varieties, like Mandarin in the flat northern plains, are more homogeneous than Southern Wu, which has a significantly greater diversity of linguistic forms, likely a direct result of the geography.

[138] Tone sandhi in Sinitic languages can occur due to phonological, syntactic, or morphological reasons, though most varieties only employ it to a limited extent.

[151][152] 昨-夜zo-yiyesterday-night小張shiaeciXiaozhang有yauhave條diaeCL大-魚dou-ngeubig-fish釣-牢。tiae-leocatch-PTCL昨-夜 小張 有 條 大-魚 釣-牢。zo-yi shiaeci yau diae dou-ngeu tiae-leoyesterday-night Xiaozhang have CL big-fish catch-PTCLXiaozhang caught a big fish yesterday night.

(Xiaoshanese [zh])Elision of the negation particle in closed question constructions is also common in Northern Wu but ungrammatical in Standard Chinese.

The literary layer was brought to the region during the Southern Song dynasty when the imperial court was moved to Lin'an, today Hangzhou.

Phonetic matching is often used due to the lack of knowledge regarding the etymologies of many terms,[185] though texts such as the Great Dictionary of Shanghainese (上海話大詞典)[175] serve as de facto recommended standardized forms,[186] as is seen in government media.

[185][186] Online communities such as Wu-Chinese and Wugniu have created pluricentric romanization systems, largely based on 19th and 20th century Western textual sources.

[191] Magnificent Dreams in Shanghai (海上繁華夢) by Sun Jiazhen (孫家振) was another example of a prostitute novel with Wu dialogue from the turn of the 20th century.

In the popular fiction of the early 20th century the usage of Wu remained in use in prostitute dialogue but, as asserted by Snow, "apparently" did not extend beyond that.