Vietnamese Tone Marks & Accented Characters Cheatsheet

Vietnamese uses the Latin alphabet with more diacritics than any other language that does, and the reason is that it stacks two independent systems on the same letter. One system modifies the vowel itself: the breve on ă, the circumflex on â, ê and ô, and the horn on ơ and ư. The other marks tone: acute for sắc, grave for huyền, hook above for hỏi, tilde for ngã and dot below for nặng, with no mark for the level ngang tone. A single vowel can carry one of each at the same time, which is how you get ệ, ữ and ộ.

Understanding that these are two separate layers makes the whole system tractable. A and ă and â are three different vowels, not one vowel with decoration — they have different sounds and appear in different words. Once you have picked the right base vowel, the tone mark is added on top of it. So ậ is the vowel â carrying the nặng tone, and ẵ is ă carrying ngã. Vietnamese has six tones and the language is genuinely tonal, so a missing tone mark changes the word: ma, má, mà, mả, mã and mạ are six different words meaning ghost, cheek, but, tomb, horse and rice seedling.

Because so much depends on the marks, Vietnamese written without them is genuinely ambiguous, and Vietnamese speakers do read stripped text in casual messaging by relying on context. It is a tolerated shortcut rather than correct writing, and in anything formal the marks are required.

The tone mark placement rule matters for correctness. In a syllable with a single vowel the mark goes on it. In a diphthong or triphthong the mark goes on the vowel carrying the main weight, and modern convention places it on the vowel with a modifier if there is one — hoà versus hòa is a genuine and long-running disagreement in Vietnamese typography, with both styles in current use. Follow whichever convention your publication uses and stay consistent.

For typing, Vietnamese uses input methods rather than direct character entry, and Telex is the most common. In Telex you type the base letters and then a key that applies the modifier or tone: aa gives â, aw gives ă, ow gives ơ, w gives ư, then s for sắc, f for huyền, r for hỏi, x for ngã and j for nặng. So typing vieejt produces việt. VNI is the alternative, using number keys for the same job. Both are available on Windows through UniKey, on macOS through the built-in Vietnamese input source, and on Linux through ibus-unikey. A final caution for data work: Vietnamese characters exist in both precomposed and decomposed Unicode forms, and mixing them breaks search — NFC normalisation is the standard remedy.