Language & WorldFact
Vietnamese is written in Latin letters, thanks to Jesuits.
For centuries Vietnam wrote in Chinese characters and the derived chữ Nôm. From 1620 Portuguese and Italian Jesuits began transcribing the language in Latin script; Alexandre de Rhodes printed a dictionary in Rome in 1651. The script stayed confined to Catholics for two centuries until the French administration enforced it in 1910. Today: 29 letters, 5 tone marks.
Useful: When you read Vietnamese, you're looking at 17th-century Portuguese spelling habits.
Source: en.wikipedia.org