With [j], like in English „yes“: https://en.wikibooks.org/wiki/Vietnamese/Consonants
It's much like the situation with the Chinese in the United States decades ago. The Cantonese-speakers immigrated first, and so traditional Chinese characters and Cantonese became well-established. The Mandarin speakers with their simplified Chinese came much later. Cantonese speakers are a relative minority in mainland China but have greater representation versus Mandarin speakers in the United States.