Shanghai dialect in the usual sense refers to the dialect in Shanghai. Shanghai dialect in a broad sense also includes Shanghai suburban dialects, such as Pudong dialect, Songjiang dialect, Jiading dialect, Chongming dialect, Jinshan dialect, Qingpu dialect, Fengxian dialect and Baoshan dialect. Usually, users of Shanghai urban dialect and suburban dialect except Shanghai county dialect do not agree that suburban dialect is Shanghai dialect. Suburban dialects other than Shanghai county dialect (old Shanghai dialect) are not so much Shanghai dialect in a broad sense, but rather other dialects mistaken for Shanghai dialect by people from other provinces and cities.
Extended data:
Shanghai dialect combines the mainstream characteristics of northern Wu dialect and becomes the fastest-growing and strongest dialect in Wu dialect area of Taihu Lake. The pronunciation of Shanghai dialect is the "greatest common denominator" and representative pronunciation of Wu dialects in various places.
Other Wu speakers can easily understand the pronunciation, vocabulary and grammatical structure of Shanghai dialect, so Shanghai dialect has the foundation and trend to become the lingua franca in northern Wu-speaking areas, and once became the lingua franca in Jiangnan areas before1980s.
Baidu encyclopedia-Shanghai dialect