Ba–Shu Chinese
Ba–Shu Chinese (; Sichuanese Pinyin: Ba¹su²yu³; ), or Old Sichuanese (or Old Szechwanese; ), is an extinct Sinitic language formerly spoken in what is now Sichuan and Chongqing, China. History and influences 
Ba-Shu Chinese was first described in the book Fangyan from the Western Han dynasty (206 BCE–8 CE) and represented one of the earliest splits from Old Chinese. It started to disappear during the late Southern Song dynasty period due to the Mongol conquest of China, which resulted in a massacre throughout the Sichuan Basin. The language was supplanted by Southwestern Mandarin after settlement by people from other parts of China, mostly from present-day Hubei and Hunan. Phonological aspects of Ba–Shu Chinese are preserved in the Minjiang dialect of Sichuanese Mandarin, which caused debate on whether the dialect is a variant of Southwestern Mandarin or a modern-day descendant of Ba–Shu. Phonology 
Although the Ba-Shu language is extinct, some phonology features of rhymes can be found by researching the local literati and poets' use of rhymes in their works. Liu Xiaonan (2014) assumed that they wrote verses in Standard Chinese of the Song dynasty, but because their mother tongue was Ba–Shu, their verses rhymed in the Ba-Shu accent. Coda mergers 
According to Liu's research, there is enough evidence to assume a significant number of coda mergers had taken place or were taking place in the Ba–Shu language during the Song dynasty:

 * and  often merged as  (). * and  often merged as  (), this progress can be abbreviated as . * and  sometimes merged as . * and  sometimes merged as . Ditto, which can be abbreviated as . *, *, and * probably all merged as , and sometimes are dropped entirely (especially in the west of the Sichuan Basin). Vocabulary 
Ba-shu language had some unique words that scholars identified as possibly being influenced by the Old Shu language. Notable speakers 
Notable speakers of the Ba–Shu language include the "Three Sūs": (, sān sū):
 Sū Shì (), who was from Meízhōu (), Chéngdū circuit (). Sū Zhé (), Sū Shì's younger brother. Sū Xún (), Sū Shì and Sū Zhé's father. See also
Ba–Shu culture
Ancient Kingdom of Ba
Ancient Kingdom of Shu
Second Kingdom of Shu
Third Kingdom of Shu
Fourth Kingdom of Shu

Notes

References

Varieties of Chinese
Extinct languages of Asia
Languages attested from the 1st millennium BC
Languages extinct in the 2nd millennium
Ba–Shu culture