Vietnamese is written in the Latin alphabet, but it is not Latin with accents added. Most letters in a Vietnamese paragraph carry diacritics, and some carry two stacked on top of each other. A brand typeface is therefore judged more by its diacritics than by its letters, and many identities fail here without anyone being able to name the problem.
Quick read: the core statement, when it comes up, and the test to take home. Full read also opens the reasoning, the limits and the sources. Each principle comes before its practices, so the numbers do not run in sequence.
In Vietnamese most letters carry diacritics, so diacritics decide the colour of the whole page; a beautiful typeface with broken diacritics is a broken typeface.
When it comes upChoosing a brand typeface, especially from international libraries that list Vietnamese support.
Resolution
A beautiful typeface with broken diacritics is no longer beautiful in Vietnamese text, because readers see diacritics on most letters.
Full reasoning
Two goods pulling against each other
On one side is a beautiful typeface with character, trusted by designers worldwide. On the other is diacritics carefully drawn for Vietnamese.
Why it holds
The typographic colour of a paragraph is the overall density of dark and light created by all its strokes. In English there are almost no diacritics, so diacritic faults stay hidden; in Vietnamese diacritics are so frequent that they decide that colour. Diacritics drawn without review by a Vietnamese reader are often too small, too thin, off-centre, or collide when stacked two deep, and Vietnamese eyes see it at once even if they cannot say why.
When it fails
A brand that uses only an unaccented name and lives mainly in foreign markets depends less on diacritics. Brand lettering that deliberately drops diacritics (9.05) is not exempt: this principle applies to every remaining accented letter in the system, from headlines and slogans to body text.
What it costs
Ruling out many beautiful typefaces, or paying extra to redraw diacritics under a licence that permits modification (9.03).
Diacritics in a hand-drawn wordmark must be drawn with the same stroke as the letters, not borrowed from another typeface.
When it comes upCustom-drawn wordmarks.
A test to take home
Check at two sizes. Enlarged: do the diacritics share the cut angles, stroke endings and contrast of the letters; diacritics that look pasted on are borrowed. Reduced to profile-picture size: do the diacritics become a dark blot or disappear before the letters? Diacritics need not be as heavy as the letter stems; they need to look equally heavy to the eye. Pass: at large size the diacritics share the hand of the letters, at profile-picture size they remain legible without becoming a blot. Fail: they look pasted on, or vanish before the letters when reduced.
Line spacing and the logo lockup of a Vietnamese brand must be measured against the letter with the tallest stacked diacritics and the lowest diacritic below, not against bare Latin letters.
When it comes upSetting line spacing (the distance between lines of text) and building the logo lockup (the fixed arrangement of words in the logo).
Resolution
Measure against the worst case that can occur in real content, and only then tighten.
Full reasoning
Two goods pulling against each other
Tightly leaded headlines look sharp and strong. Capitals with stacked diacritics such as Ẩ, Ỗ, Ữ need room above.
Why it holds
The Latin type frame is calculated from the cap height. Vietnamese diacritics, especially tone marks placed on a circumflex (â, ê, ô) or a breve (ă), add one or two tiers above that height; the dot below a capital reaches down into the space between lines. Line spacing calculated for Latin lets the diacritics of one line touch or overlap the descenders of the line above. In the real world, that is a name printed tight against the top edge of a carton or lightbox: Ổ and Ẫ lose their diacritics and read as other letters. On websites, a text container that clips overflow cuts off diacritics without reporting an error. And a type system rarely breaks on handover day; it breaks on the day the business names its tenth product with an Ặ or Ữ in it.
When it fails
Lockups and slogans cast in fixed form and approved letter by letter are exempt from the line-spacing measurement; they are not exempt from the lockup step of 9.06 about room for sub-product names. Lowercase headlines are not exempt: lowercase letters with stacked diacritics such as ẫ and ổ can be as tall as or taller than bare capitals.
What it costs
Headlines look airier than international specimens; accept it, or redraw lower diacritics specifically for large sizes.
Test a typeface with Vietnamese words carrying stacked diacritics and diacritics below, not with an English pangram.
When it comes upThe first round of typeface selection, and when setting line spacing and building the logo lockup.
A test to take home
(1) Type exactly this set: ẤN ĐỘ · ỔN ĐỊNH · KỶ NIỆM · NHỮNG · THẲNG · LẶNG · BẬT · TRƯỜNG · NGƯỠNG · Nghiêng ngửa, Ngưỡng cửa, Lượm lặt, Tưởng tượng, ẵm bồng. (2) Check five things: do tone marks collide with the circumflex or breve; do the horns of capital Ư and Ơ crash into the diacritics of neighbouring letters; is the dot below ư and ơ aligned with the letter body; are the hook above and the tilde still distinguishable at the smallest screen size; retype the sentence using the Unikey input method set to the combining Unicode table (separate diacritics, see 9.09) and open it at 12 to 14px on a real Windows machine: diacritics detached from letters mean the typeface has not implemented mark positioning, diacritics fused to letters or broken strokes mean it does not yet render well on screen. (3) Line spacing (9.02): set two lines one above the other, the upper with g, p, y, the lower with Ẫ, Ỗ, at the real size; there must be a white gap between the top of the diacritic and the descender. Type the sequence Ẫ Ằ Ỗ Ữ (separate characters, not a word) at large size in Word on Windows: clipped tops mean the font file declares a height lower than its tallest diacritic, which line spacing cannot fix; change typeface or fix the font file. Type the same sequence in a browser: clipping there is usually caused by the text container, fixed in the container. (4) Lockup: type the brand name and three hypothetical sub-product names with stacked diacritics, including letters with marks both above and below (Ặ, Ậ), in the exact logo lockup; any diacritic with no room is where the system will break as the business grows. For a deliberately unaccented lockup, set those three names beside it: the accompanying accented words must have room without breaking the lockup. (5) Real materials (9.04): print the smallest line on the actual paper or vinyl to be used, including a white-on-colour version if the packaging has one; for offset printing require a proof on the right paper, for thermal printers print on the actual machine at the resolution it will run; give it to someone who has not read the content to read aloud. Pass: no diacritics collide, touch the line or are clipped, the three sub-names fit the lockup, and the reader reads every diacritic correctly. Fail: one diacritic touches the line above, is clipped in Word or the browser, or the reader misreads even one diacritic.
A typeface stays in a brand for long only when the business has the right to use it at every touchpoint; without that right it is a debt.
When it comes upChoosing brand typefaces, especially when using Vietnamese-localised versions circulating online. A touchpoint here is any place a customer meets the brand: print, signage, website, apps, video, documents.
Resolution
A typeface you have no right to use is a debt waiting to be called in, however beautiful its diacritics.
Full reasoning
Two goods pulling against each other
Ready-made Vietnamese versions are fast, cheap, and often have decent diacritics. The right to use requires licences for print, web, apps and video.
Why it holds
Type licences are usually divided by use (desktop, web, app, embedding in files), and many forbid modifying the original. Localising for Vietnamese is modifying. The bigger the brand and the more places it appears, the greater the risk of a rights claim, and changing typefaces after years of use loses part of the recognition. Many localised versions circulating online were built from originals licensed for personal use only; whether they are lawful is decided by the original's licence, not by whoever localised it. A logo with lettering converted to outlines no longer needs the font file to display, but the right to use those letterforms is still governed by the licence: many licences allow use in logos, some require a separate licence or forbid registering trademarks containing the lettering. For a logo intended for trademark registration, read that exact clause before finalising.
When it fails
Typefaces under open licences that permit modification and commercial use, such as the SIL Open Font License, provided the modified version is renamed if the original declares a reserved font name.
What it costs
Licence costs, or narrowing the choice to typefaces with clear licences.
A brand's Vietnamese lettering fails at the diacritics first, so approve it at the worst touchpoint it will certainly meet, not on the designer's screen.
When it comes upApproving lettering for an identity that will go into print, signage, embroidery, engraving, thermal printers, images compressed when sent through messaging apps, small profile pictures, and places where text passes through machines: search boxes, databases, file names.
Resolution
The letter stems keep one form; diacritics may have their own version for small sizes and rough materials, provided readers still read every diacritic correctly and a glancing viewer does not see two typefaces. The rule of approving at the worst touchpoint belongs to 10.03 and 8.01; this principle only states what is particular to Vietnamese: the first thing to fail is the diacritics, and when diacritics fail the word reads as a different word, not merely an uglier one.
Full reasoning
Two goods pulling against each other
On one side is keeping one letterform at every size and on every material: consistent, easy to manage, customers meet the same lettering everywhere (12.01). On the other is letting diacritics adapt to where they live: larger, heavier, with wider gaps at small sizes and on rough materials, because diacritics are the smallest strokes and die before the letter stems.
Why it holds
Diacritics are the smallest strokes of Vietnamese lettering, so they die first at small sizes, when ink spreads on uncoated paper, when embroidery thread has too few stitches, or when a thermal printer prints at low resolution. The dot below is usually lost first; the hook above and the tilde spread into a smear and become indistinguishable. Some touchpoints the eye cannot see: text looks right on screen while the machine reads a different string, so the search box finds nothing and links do not match (9.09).
When it fails
A brand that lives only on high-resolution screens at large type sizes is exempt only from the materials part; the part where text passes through machines is not exempt.
What it costs
Sometimes a separate lettering version is needed for small sizes and rough materials.
On dimensional letters and cut signs, each diacritic is a separate piece and must be designed as a separate piece.
When it comes upDimensional sign letters, cut acrylic letters, illuminated letters, letters carved into walls.
A test to take home
On the fabrication drawing, every diacritic has a means of fixing (pins, adhesive, frame) and a distance from its letter sufficient to read at the real viewing distance. A drawing that does not state how diacritics are fixed is unfinished. For illuminated letters, measure the diacritic's stroke width against the smallest channel width the workshop can build, for the type of lighting it uses (modules or LED strip); a diacritic too small to hold lighting must be decided on the drawing (enlarged, unlit, or bridged), not left for the workshop to improvise during fabrication. Pass: every diacritic on the drawing has its fixing and distance stated, and illuminated diacritics have a chosen treatment. Fail: the workshop has to ask how to mount the diacritics, or decides during fabrication.
Normalise all Vietnamese text to the precomposed form (NFC) at the point where text enters the system, before it reaches the website, the database or print files.
When it comes upContent copied from many sources, file names from Macs, input methods set to the combining Unicode table (separate diacritics), product data imported in bulk through forms, Excel files, uploaded images. Old text in the TCVN3 or VNI encodings must first be converted to Unicode; NFC normalisation cannot fix it. The letter ế can be stored as one complete character, or as e with circumflex plus a separate acute accent. On screen the two look identical; a machine comparing them sees two different strings, like two banknotes that look alike but have different serial numbers, so the search box cannot find a name that is visibly on the page and image file names from Macs do not match paths on the server.
A test to take home
(1) Copy the word "Việt" from the website, from the database and from the input method of the staff entering data into a character counter: 4 means precomposed, 5 or 6 means separate diacritics. (2) Search the website for an accented name using its search box. Pass: all three sources give 4, and the search box finds the name. Fail: one source gives 5 or 6, or the search box finds nothing although the name is on the page, or diacritics appear misaligned relative to surrounding text: the data mixes two forms and must be normalised where text enters.
Sources
Sources
Unicode Standard Annex #15, Unicode Normalization Forms
W3C, Character Model for the World Wide Web: String Matching
Dropping diacritics from a name gives away part of its meaning; give it away only for a reason written down, after asking who the main reader will be over the next five years.
When it comes upNaming or drawing the name lettering for a business with a Vietnamese name.
Full reasoning
Two goods pulling against each other
Dropping diacritics makes domains easier to register, the name easier for foreigners to read, and the lettering tidier. Keeping them keeps the meaning, the sound, the roots. Resolve it with the question of who the main reader will be over the next five years, not which version looks cleaner.
Why it holds
Dropping diacritics removes more than strokes; it changes meaning and pronunciation: one unaccented name can correspond to several accented names. When diacritics are dropped for the sake of appearance, the business has given away part of its meaning without anyone weighing what it gets in return.
When it fails
Borrowed or coined names have no diacritics to begin with. When the client named and registered the business before the studio was engaged, the studio does not reopen the name; an unaccented version not yet defined is still checked under 9.10, the risk is stated in writing, and the decision is the client's. Brand lettering may stand without diacritics when three conditions hold: it is the defined unaccented version of the name (9.10), the reason for dropping diacritics is recorded in the guidelines, and wherever people read text the name is still written with full diacritics. Missing one condition means dropping diacritics for appearance.
What it costs
Keeping diacritics means living with two versions of the name: an accented one for readers and an unaccented one for domains, accounts and systems that cannot type diacritics. Names with the rhymes oa, oe, uy carry an extra choice of tone-mark placement (hoà or hòa), and that choice must also be settled once (9.10).
The unaccented version of the name and its tone-mark placement must be defined once and written into the guidelines, from the day of naming or from today if not yet done.
When it comes upAn accented name that must be used in domain names, social media accounts, bank accounts and systems that cannot type diacritics; names or brand copy with rhymes such as oa, oe, uy (hoà or hòa, thuỷ or thủy).
A test to take home
(1) Write two lines into the guidelines. Line one, the unaccented version: whether đ becomes d or dd, how it is capitalised, whether words are joined, hyphenated or underscored, with the reason. Line two, tone-mark placement (hoà or hòa), following the name on the business registration certificate if the registered name has the rhymes oa, oe, uy, and preset in the input methods of the people who type the name most (sales, accounting, communications). (2) List every place the name appears and compare with those two lines: any place written differently without a reason recorded in the guidelines is a place where the brand carries an extra name. When two tone-mark placements coexist, search boxes treat them as two names, and invoices or documents that differ from the registered name may have to be redone. (3) Write out the unaccented version and have three strangers read it and guess the original name; if most first read a word with a bad meaning, the unaccented version needs fixing. Pass: the guidelines have both lines, every place the name appears matches them or has a recorded reason, and strangers read back the original name. Fail: a place written differently without reason, two tone-mark placements coexisting, or the unaccented version read as a word with a bad meaning.
