Taizhou dialect circle, generally known as Tairu (Taizhou-Rugao) dialect film or Tongtai (Nantong-Taizhou) dialect film academically, is a sub-region of Xiajiang Mandarin (also known as Jianghuai Mandarin). This paper is hereinafter referred to as "Taizhou Dialect Circle". Taizhou dialect circle includes Taizhou, Jiangyan, Taixing, Xinghua, Hai 'an, Rugao, Rudong (Northwest), Dongtai and Dafeng, covering three prefecture-level cities of Taizhou, Nantong and Yancheng, with a total population of about 9 million.

Taizhou dialect circle, located in the core area of central Jiangsu, is geographically adjacent to the sea in the east, the Yangtze River in the south, the Huaihe River in the north and Yangzhou in the west. Historically, this area was under the jurisdiction of Taizhou. After liberation, the prefecture-level Taizhou area was administratively revoked. Hai 'an and Rugao (including Rudong) in the southeast merged into Nantong, Dongtai and Dafeng in the northeast merged into Yancheng, and Taizhou itself and the counties west of the original Taizhou area merged into Yangzhou, becoming the county-level areas of Yangzhou. This is why I call this area "Taizhou Dialect Circle".