For which of these languages is the Latin script used?

Vietnamese (Tiếng Việt) is an Austroasiatic language that originated in Vietnam, where it is the national and official language. Spoken natively by an estimated 76 million people (as of 2009), it is the native language of the Vietnamese (Kinh) people, as well as a first or second language for the many ethnic minorities of Vietnam.

Vietnamese is the Austroasiatic language with by far the most speakers, several times as many as the rest of the family combined. Its vocabulary has borrowings from Chinese, and it formerly used a modified set of Chinese characters called Chữ Nôm, which were given vernacular pronunciation. The Vietnamese alphabet in use today is a Latin alphabet with additional diacritics for tones and certain letters.

Up to the late 19th century, two writing systems based on Chinese characters were used in Vietnam. A romanization of Vietnamese was codified in the 17th century by the French Jesuit missionary Alexandre de Rhodes, based on works of earlier Portuguese missionaries Gaspar do Amaral and António Barbosa. This Vietnamese alphabet was gradually expanded from its initial domain in Christian writing to become more popular among the general public. However, the Romanized script did not come to predominate until the beginning of the 20th century, when education became widespread and a simpler writing system was found more expedient for teaching and communication with the general population.