Is the last name Do Chinese or Vietnamese?
You can’t tell just by looking at the romanized pronunciation because as far as I know most East Asian continental names have a single sound/syllable. Although “Do” isn’t the conventional way of writing a Chinese family name it could have been localized by the Vietnamese language. Chinese Cantonese names prefer to use “To” instead of “Do” and Chinese Mandarin names wouldn’t have such a sharp sound eg. “D” sounds would usually be spelt “Dao” “De” “Di”, I don’t recall Mandarin having a “Do”. However there is a recognized Chinese surname 杜 (Cant: To, Mand: Du). Update: I see they speak 潮州話 so they must be 潮州人 Teochew-ese. The Teochew folks are definitely from (east of) Guangdong or Canton. So they are indeed of Cantonese ancestry.
