1) Areas that were once predominantly Wu Chinese-speaking (Chuzhou 滁州 during the Wei-Jin period and Yangzhou during the Sui-Tang dynasties) are now Jianghuai Mandarin-speaking. Chuzhou Wu was supplanted by an early Jianghuai Mandarin during the Southern Song period. Xuancheng Wu itself is currently being replaced by Jianghuai Mandarin and facing extinction. Nanjing itself also had a majority Wu-speaking population, with a dwindling minority who still speak Wu, particularly confined to areas outside of the city proper itself. So the Wu-speaking domain used to be much larger in the past, it could have occupied much of Anhui province as well as at least 60% of Jiangsu province.
2) Growth of Jianghuai Mandarin often coincided with devastating events that affected the Wu-speaking domain. (The enforcement of the Queue Order is said to have resulted in hundreds of thousands of deaths in a series of massacres throughout southern Jiangsu and northern Zhejiang due to the non-compliance of the locals; the Taiping rebellion has also had devastating effects on the Wu-speaking population) From a native-speaking population that was once about 20% of the entire Chinese population during the late Ming-early Qing period, to approximately 14% on the onset of the Taiping rebellion, to approximately 5-7% today (if looking at the Ethnologue estimated population of approximately 77 million, though I think the actual number of speakers has sharply decreased to approx. 40-55 million competent speakers) and decreasing. A portion of southern Anhui and northwestern Zhejiang was heavily depopulated during the Taiping period until it was repopulated by northern Chinese migrants from Hubei and Henan. A result of the Taiping rebellion was the sharp decline of Suzhou dialect as the prestige dialect of Wu Chinese, only to be replaced by Shanghainese as the prestige Wu dialect.
Though the above quote is true that there were massacres during the enforcement of the Queue Order by Dorgon, the figures given (a outrageously large death toll of 8-9 million in Jiaxing alone!) are dubious, but could be possible due to the relative population density. Through this theory, resistance to the Queue Order was the strongest in the Wu-speaking areas.
3) Evidence of Wu-speaking enclaves in Jianghuai-Mandarin speaking domains. A particular case of interest is some dialects of Guangde County in southern Anhui and some Wu-speaking enclaves in the area between the Huai river and the Yangtze.
4) The negative stereotypes that Wu-speakers have towards Jianghuai Mandarin speakers, as shown here: http://www.chinahist...-for-nishishei/ This is closely paralleled with the situation of the stereotypes that Greeks (including Greek Cypriots) have towards Pontian Greeks. Pontian Greeks and Jianghuai Mandarin speakers have both been stereotyped as stupid or imbecilic by both Greeks and Wu-speakers, respectively. This is just an analogy. Although the quoted thread states that there was just bad blood between 'southern' Wu-speaking Jiangnanese and 'northern' Jianghuai Mandarin speakers, I believe that there was something more historically linked that could lead to this stereotype, which is why I made a comparison with Pontian Greeks who suffered through some similar ordeals. There are still Wu-speakers living in areas north of the Yangtze.
5) Jianghuai Mandarin itself has a Wu substratum on top of that. There are some Jianghuai Mandarin speakers who firmly believe that their language is not Wu Chinese, despite many similarities. Some Jianghuai dialects still preserve some MC voiced initials to a degree, particularly Hefei dialect in one of its registers.
This is just a theory, and do take this with a grain of salt. (Though I may fear that certain Sinophobic individuals may twist this around and use this to serve their own agenda)
Edited by bloodmerchant, 27 April 2011 - 06:10 PM.