Do you think you understand most dialects in your own language?

nope I remember once in Shanghai there was this older grandma who was speaking mandarin with the heaviest shanghai accent and I barely understood that

American English - yes

Vietnamese - nooooo... my Vietnamese is very basic

American English- Yes

Chinese- Absolutely Not as there are so many distinct dialects across China (some even confusing speakers of different dialects literally right nearby)

Spanish- Nah, I don't speak too much Spanish anymore but I do understand it of course. Technically it's my first language, but I wouldn't say Spanish is my main language at all