That’s why it’s odd to call it a dialect, yet by definition it is, mostly because it’s spoken by the similar ethnic group that originated from the same or neighbouring region, and by that definition mandarin is a dialect as well, just that china decided to make it a common language of the chinese. Like 粤语, it’s originated from guan dong but in china it’s a dialect, yet in british era hong kong it’s their common language. The same thing for 闽南语 in taiwan, which originated from fu jian.

But even though it’s different, if you know multiple dialect you can actually roughly understand the dialect you don’t know. Well, roughly.

like 海闊天空 (song) is my favorite thing to listen to in Cantonese)

RIP Beyond.