吳 - Wu2 - (a surname), An ancient kingdom, A group of related dialects

I always thought that Cantonese was the second most commonly spoken dialect of Chinese. I was wrong! It’s actually a group of related dialects called 吳, which Shanghainese is a part of. Here’s the breakdown of the major groups and numbers of speakers. And if you want to explore this subject even more, look no further than the astoundingly detailed Chinese Dialects section of Glossika.com.