[tonylinn80]

I speak a branch of Wu myself, and it's ABSOLUTELY not a different language from other dialects of Chinese. There are small parts (also commonly used) of the dialects that's dramatically different from Mandarin, but most parts are still the same. Especially if you need to speak about things in a more formal context, or describe concepts that are more abstract, the dialects has no difference with each other if written down

[jacobolus]

The pronunciation of words in Wu Chinese and Mandarin is systematically different, and many common words are entirely unrelated. Typical Mandarin speakers can’t understand Wu Chinese at all.

The relationship is similar to that between English and German or French and Italian.