Shanghainese is the
local dialect spoken by the people who live in
Shanghai and the area surrounding it. It belongs in a larger group of
dialects,
Jiangsunese, after the
Jiangsu province.
Jiangsu is a big place, just like most other chunks of
Chinese dialects,
Jiangsunese is quite
diverse, each major
city has their own
dialect.
Shanghainese is the major
dialect of the region, however, it is completely different from
Nanjingnese, the other major
dialect of the
province. I suspect that
Shanghainese developed from either
Nanjingnese (the
Nanjing dialect) or
Suzhounese (
Suzhou), for
Shanghai was little more than a
fishing village a few centuries back, and
Nanjing has been around for eons,
Suzhou even longer. My rudimentary knowledge of
Shanghainese leaves me no chance of understanding any of the other
Jiangsu dialects.
Shanghainese is notoriously difficult to learn, even more so than Cantonese, because a large part of their characters are only known through the word of mouth and never written down. Almost all Chinese dialects have their little special terms, however, Shanghainese has far too many. It is spoken in a rolling brogue; Shanghainese is like the Irish dialect of Britain. Odd accents in strange places. I don't know a single foreigner who speaks good Shanghainese. Save Harrison Ford in the intro to the movie "Temple of Doom", but he had a bad accent. Narf.
As one goes west from Shanghai, other dialects in the family can be found, from Wuxi to Nanjing, all unique. The seemingly oral tradition of the Jiangsu dialects is interesting, however, it is probably because I am not a native speaker. There are many tones (or consonants) in this dialect, perhaps as much as Cantonese, however, the lack of written material prevents me from doing research.
An interesting sidenote is that many famous Chinese poets came from this region. Poems, if read in different dialects, sound quite horrible, but when they are dictated in the poet's native dialect it makes much more sense. This testifies to the ongoing evolution of the Chinese language, these dialects have been developing for centuries.