Shanghai used to belong to Songjiang prefecture and was once under the jurisdiction of Jiaxing, and its language was mainly Jiaxing dialect. Suzhou dialect is one of the important representative sound sources of Wu dialect in the phonetic composition of Shanghai dialect. In addition, the Ningbo dialect of Wu dialect, which was dominant among modern immigrants, also had a far-reaching influence on Shanghai dialect.

Jiaxing dialect is very different from Suzhou dialect and Shanghai dialect. Please refer to Baidu Encyclopedia for details.