Updated 2 February, 2023
This page brings together basic information about the Tai Viet script and its use for the Tai Dam language. It aims to provide a brief, descriptive summary of the modern, printed orthography and typographic features, and to advise how to write Tai Dam using Unicode.
ꪭꪴꪒ 1 ꪹꪕꪸꪉ ꪀꪱ ꪋꪴ ꫛ ꪎꪲꪉ ꪮꪮꪀ ꪣꪱ ꪻꪠ ꪁꪷ ꪻꪬ ꪼꪒ ꪕꪳ ꪕꪱꪉ ꪀꪾꪚ ꪹꪋꪷꪉ ꪝꪸꪉ ꪕꪮꪥ ꪩꪾ ꫛ ꪶꪔꪙ ꪠꪴ - ꪋꪴ ꪬꪺ ꫛ ꪻꪠ ꪁꪷ ꪻꪬ ꪣꪲ ꪁꪫꪸꪙ ꪎꪱꪉ ꪶꪎꪣ ꪩꪺꪉ ꪹꪥꪸꪒ ꫛ ꪀꪾꪚ ꪹꪥꪸꪒ ꪻꪊ ꪚꪴꪙ ꪀꪾꪚ ꪼꪒ ꪹꪚꪷꪉ ꪒꪲ ꪀꪾꪚ ꪫꪸꪀ ꪭꪰꪀ ꪵꪝꪉ ꪹꪏꪉ ꪹꪭꪙ ꪒꪸꪫ.
ꪭꪴꪒ 2 ꪋꪴ ꫛ ꪻꪠ ꪁꪷ ꪝꪮꪣ ꪼꪒ ꪹꪬꪉ ꪝꪳꪉ ꪁꪫꪸꪙ ꪹꪜꪸꪙ ꪹꪊꪱ ꪀꪾꪚ ꪕꪳ ꪕꪱꪉ ꪹꪏꪉ ꪹꪫꪱ ꪀꪺꪉ ꪻꪚ ꪜꪱꪫ ꪁꪫꪱꪣ ꪙꪲ, ꪹꪚꪱ ꪜꪽ ꪵꪊꪀ ꪹꪋ ꪡꪽ - ꪹꪙ ꪘꪰꪉ - ꪻꪊ ꪈꪾ - ꪁꪫꪱꪣ ꪜꪱꪀ - ꪭꪲꪒ ꪅꪮꪉ - ꪩꪺꪉ ꪜꪴꪙ ꪵꪔꪉ ꪀꪨꪰꪒ ꪄꪮꪉ ꪹꪊꪱ ꪭꪳ ꪫꪱ ꪩꪺꪉ ꪀꪨꪰꪒ ꪮꪳꪙ, ꪶꪀꪀ ꪹꪅꪱ ꪹꪬꪱ ꪭꪱꪀ ꪚꪱꪙ ꪹꪣꪉ ꪬꪱꪀ ꪣꪲ ꪭꪳ ꪫꪱ ꪚꪱꪙ ꪹꪣꪉ ꪙꪾ ꪣꪲꪉ ꪎꪲꪉ ꪄꪮꪉ. ꪄꪮꪉ ꪹꪊꪱ ꪬꪱꪀ ꪼꪒ ꪬꪱꪀ ꪣꪲ ꪭꪳ ꪫꪱ ꪹꪜꪸꪙ ꪵꪔ ꪚꪱꪙ ꪹꪣꪉ ꪕꪰꪒ ꪮꪮꪀ.
The Tai Viet script is used for writing the Tai Dam (Black Tai or Tai Noir), Tai Dón (White Tai or Tai Blanc), Tai Daeng, Thai Song (Lao Song or Lao Song Dam) and Tày Tac languages spoken in Vietnam, Laos, China and Thailand. There is also a diaspora in the United States, Australia and France.
The total population using the three languages, across all countries, is estimated to be 1.3 million (Tai Dam 764,000, Tai Dón 490,000, Thai Song 32,000). The script is still used by the Tai people in Vietnam, and there is a desire to introduce it into formal education there.
Little is known about the origin of the Tai Viet script. It appears to have been derived from the Thai script around the 16th century.
Significant variation occurs in the orthographic conventions of the Tai languages, as well as in their phonologies. A unified, standardized version of the script, with an agreed upon core set of characters, was developed at a UNESCO-sponsored workshop in 2006, and subsequently accepted for encoding in The Unicode Standard.
Sources: Scriptsource, The Unicode Standard.
The script is an alphabet. Both consonants and vowels are indicated by letters. See the table to the right for a brief overview of features for the modern Tai Dam orthography.
The Tai Viet script is heavily syllable-based, with exceptions being a very small number of unstressed initial syllables, and loan words.
Tai Viet text runs left to right in horizontal lines.
Words are separated by spaces, although this is a recent innovation.
Tai Dam uses 42 consonant charactes, all neatly divided into 2 classes. Each consonant is associated with a high or low class to indicate tone. Tone is indicated by a combination of the consonant class, the syllable type (checked/unchecked), plus any tone mark. ❯ consonants
There are no conjuncts or subjoined consonants.
The only syllable-initial cluster involves labialisation, using ꪫ w. ❯ onsets
Syllable-final consonant sounds use a subset of 8 ordinary consonant letters, but since there is no inherent vowel, it is still simple to detect syllable boundaries. Syllable-final consonant sounds are also built into 6 vowel-consonant graphemes. ❯ finals
The Tai Dam orthography has no inherent vowel, and represents vowels using 15 vowel signs (including 5 pre-base), and 5 consonants. Vowel signs are a mixture of ordinary spacing characters, and combining marks. ❯ vowels
There are no independent vowels, and standalone vowel sounds use a vowel sign attached to ꪮ [U+AAAE TAI VIET LETTER LOW O] or ꪯ [U+AAAF TAI VIET LETTER HIGH].
This page lists only 6 composite vowels, made from 6 vowel signs and 3 consonants. Composite vowels can involve up to 3 glyphs, though usually only 2, and glyphs can surround the base consonant(s) on 2 sides. ❯ composite_vowels
Tone can be indicated either by diacritics or ordinary spacing characters. Both are a recent innovation. Combining tone marks always follow the root consonant and any combining vowels, ie. they come before any post-base vowel. Spacing tone marks always come at the very end of the syllable. ❯ tones
These are sounds for the Tai Dam language.
Click on the sounds to reveal locations in this document where they are mentioned.
Phones in a lighter colour are non-native or allophones.
|stop||p b||t d||k ɡ||ʔ|
r and ɡ are used in Vietnamese names.
The Tai languages are almost exclusively monosyllabic. A very small number of words have an unstressed initial syllable, and loan words may be polysyllabic.b
The essential character sequence of a Tai Viet syllable is:
pre-base vowel?, root consonant(s), combining vowel?, post-base vowel?, final consonant?
The root consonant(s) may be a cluster involving labialisation. Any combining vowel goes after the root consonant(s).
Tone marks expressed as combining characters always follow the root consonant(s) and any combining vowels, which means that they come before any post-base vowel.
Tone marks expressed as spacing characters always come at the very end.
-ap. One other sequence occurs when writing the vowel-final consonant combination -ap, which is written with a vowel placed over the final low-series b, rather than over the initial consonant, eg. ꪁꪚꪾ kap
The sequence is:
root consonant(s) + ꪚꪾ [U+AA9A TAI VIET LETTER LOW BO + U+AABE TAI VIET VOWEL AM]
See gpos, however, for a font variant setting that allows you to store the code points in the normal order, but still display the AM over the BO.
ꪁꪰ ka U+AA81 TAI VIET LETTER HIGH KO + U+AAB2 TAI VIET MAI KANG
There is no inherent vowel, so the sound ka, which would in an abugida be written just using a consonant, is also spelled out using a vowel sign.
Vowels in Tai Dam are written with a mixture of combining characters and ordinary spacing characters. It is also common to use some consonants to represent vowel sounds (see consonant_vowels). Several vowel signs combine a vowel and a final consonant, or represent diphthongs.
Tai Viet uses visual placement: only the vowel components that appear above or below the consonant are combining marks; the others are ordinary spacing characters that are typed in the order seen.
ꪁꪲ ki U+AA81 TAI VIET LETTER HIGH KO + U+AAB2 TAI VIET VOWEL I
Tai Dam uses the following combining marks for vowels.
ꪁꪺ kuə U+AA81 TAI VIET LETTER HIGH KO + U+AABA TAI VIET VOWEL UA
The following additional, vowel-specific characters are ordinary spacing characters, with the general category of 'letter'. Many of these are typed and stored before the base consonant (see prebase).
Of the spacing characters, 5 appear before the onset consonant (see prebase), and the following 3 appear after:
ꪱ [U+AAB1 TAI VIET VOWEL AA]
ꪽ [U+AABD TAI VIET VOWEL AN]
ꪺ [U+AABA TAI VIET VOWEL UA]
ꪶꪁ ko U+AAB6 TAI VIET VOWEL O + U+AA81 TAI VIET LETTER HIGH KO
Five vowel signs appear to the left of the onset consonant after which they are pronounced.
Like Lao, Tai Viet uses a visual encoding model, so these characters are not combining characters, but are typed and stored before the base. For example:
Note that ꪵ [U+AAB5 TAI VIET VOWEL E] should not be typed as two successive ꪹ [U+AAB9 TAI VIET VOWEL UEA] characters.
These vowel signs are placed before the start of the syllable onset. This means that in a word with more than one consonant at the start (ie. a labialised consonant) the pre-base vowel is placed to the left of the syllable-initial consonant, rather than to the left of the consonant after which it is pronounced.
fig_prebase shows an example to graphically illustrate the relationships between the characters.
ꪁꪮ kɔ U+AA81 TAI VIET LETTER HIGH KO + U+AAAE TAI VIET LETTER LOW O
The following characters are also used to create vowel sounds, either alone or as part of a composite vowel.
ꪮ [U+AAAE TAI VIET LETTER LOW O] and ꪯ [U+AAAF TAI VIET LETTER HIGH] can represent vowels on their own. The following word in fact shows the same character being used as both consonant and vowel in the same word.b
The others are used in combination with other vowel signs, see composite_vowels.
ꪹꪁꪸ ke U+AAB9 VOWEL UEA + U+AA81 LETTER HIGH KO + U+AAB8 VOWEL IA
Vowels represented by combinations of the above characters include the following, which mostly add glyphs to different sides of the base:
Pre-base and post-base vowel glyphs are split around the syllable onset, which may be more than a single character. fig_prebase shows an example.
ꪫ [U+AAAB TAI VIET LETTER HIGH VO] can be ambiguous in this combination unless there is a tone mark. The sequence ꪵ–ꪫꪥ [U+AAB5 TAI VIET VOWEL E + U+AAAB TAI VIET LETTER HIGH VO + U+AAA5 TAI VIET LETTER HIGH YO] is sometimes used to remove that ambiguity. For details, see onsets.
The last item in the list is rather unusual. Some dialects use the combination ꪚꪾ [U+AA9A TAI VIET LETTER LOW BO + U+AABE TAI VIET VOWEL AM] to make -ap,b,7 eg. ꪀꪚꪾ There are 2 possible code point orders that can be used for this: see structure.
Characters that don't appear in the combinations:
The following list shows where vowel signs are positioned around a base consonant to produce vowels, and how many instances of that pattern there are. The figure after the + sign represents combinations of Unicode characters,
There are no independent vowels, and Tai Viet represents what look like standalone vowels using a vowel sign attached to ꪮ [U+AAAE TAI VIET LETTER LOW O] or ꪯ [U+AAAF TAI VIET LETTER HIGH], and phonetic transcriptions include an initial glottal stop.
This section maps Tai Dam vowel sounds to common graphemes in the Tai Viet orthography. Click on a grapheme to find other mentions on this page (links appear at the bottom of the page). Click on the character name to see examples and for detailed descriptions of the character(s) shown.
–ꪲ [U+AAB2 TAI VIET VOWEL I], eg. ꪔꪲꪫ .
–ꪳ [U+AAB3 TAI VIET VOWEL UE], eg. ꪜꪳꪙ .
–ꪴ [U+AAB4 TAI VIET VOWEL U], eg. ꪄꪴ꪿ꪙ .
ꪹ–ꪸ [U+AAB9 TAI VIET VOWEL UEA + U+AAB8 TAI VIET VOWEL IA], eg. ꪹꪔꪸꪣ .
ꪶ– [U+AAB6 TAI VIET VOWEL O], eg. ꪶꪁꪙ .
–ꪷ [U+AAB7 TAI VIET MAI KHIT], eg. ꪝꪷ .
ꪮ [U+AAAE TAI VIET LETTER LOW O], eg. ꪮꪮꪀ .
–ꪰ [U+AAB0 TAI VIET MAI KANG], eg. ꪔꪰꪒ .
ꪱ [U+AAB1 TAI VIET VOWEL AA], eg. ꪮ꪿ꪱꪉ .
ꪸ [U+AAB8 TAI VIET VOWEL IA], eg. ꪣꪸ .
ꪹ– [U+AAB9 TAI VIET VOWEL UEA], eg. ꪹꪎ .
ꪺ [U+AABA TAI VIET VOWEL UA], eg. ꪎ꫁ꪺꪉ .
ꪵ–ꪫ [U+AAB5 TAI VIET VOWEL E + U+AAAB TAI VIET LETTER HIGH VO]
ꪵ–ꪫꪥ [U+AAB5 TAI VIET VOWEL E + U+AAAB TAI VIET LETTER HIGH VO + U+AAA5 TAI VIET LETTER HIGH YO] in some dialects, to avoid ambiguity, eg. ꪵꪁꪫꪥ .
ꪻ– [U+AABB TAI VIET VOWEL AUE], eg. ꪻꪐ꪿ .
ꪼ– [U+AABC TAI VIET VOWEL AY], eg. ꪼꪒ꫁ .
ꪹ–ꪱ [U+AAB9 TAI VIET VOWEL UEA + U+AAB1 TAI VIET VOWEL AA], eg. ꪹꪉꪱ .
–ꪾ [U+AABE TAI VIET VOWEL AM], eg. ꪁꪾ .
ꪽ [U+AABD TAI VIET VOWEL AN], eg. ꪜ꫁ꪽ .
ꪚꪾ [U+AA9A TAI VIET LETTER LOW BO + U+AABE TAI VIET VOWEL AM], eg. ꪀꪚꪾ .
Until the latter part of the 20th century Tai Viet didn't mark tones other than by the consonant class. Since then, however, 2 methods have developed.
Tai Dam speakers in the United States and speakers of the Song language borrowed combining tone marks from Lao/Thai.
These tone marks are typed and stored immediately after any combining vowel sign, if there is one, otherwise after the initial consonant(s).
The Tai community in Vietnam developed an alternative approach, where tone is marked by ordinary spacing characters that are typed and stored after all other elements in the syllable.
The following chart shows how to tell which tones are associated with a syllable.
|꪿ or ꫀ||5|
|꫁ or ꫂ||6|
|꪿ or ꫀ||2|
|꫁ or ꫂ||3|
The letters ʰ and ˡ below each character indicate whether the class is high or low.
Three pairs of consonants are used for the Tai Don language, but not for Tai Dam.btd They are:
The consonant wa can appear immediately after the initial consonant in a syllable. It is written using ꪫ [U+AAAB TAI VIET LETTER HIGH VO].
The pronunciation of a syllable containing WA in non-initial position can be ambiguous, unless there is a diacritic, since the WA may or may not be a final consonant.b Compare ꪀꪲꪫ ḵiw ꪀꪫꪲ ḵwi and ꪵꪀ꫁ꪫ ɛḵ²w kʷɛ ꪵꪀꪫ꫁ ɛḵw² kɛw
In order to address the latter ambiguity, the character ꪥ [U+AAA5 TAI VIET LETTER HIGH YO] is sometimes appended to the end of the sequence to indicate the second pronunciation, eg. ꪵꪁꪫꪥ Since j never occurs after ɛ, this can be done without creating a new ambiguity. This spelling is only used in some dialects of the traditional script, however, it has been adopted as a standard in a project sponsored by the Son La Department of Science and Technology.b
The sound kʰʷ exists in Tai Don, but not in Tai Dam. The sound kʷ exists in both languages.btd
Syllable-final plosives are written using the following low class consonants. These create 'checked' syllables.
For open syllables ending with nasals or glides, the following high class consonants are used.
In addition, several vowels carry a final consonant. See vowels. These include:
Consonant clusters occur in the following circumstances:
No special characters or viramas are involved, in any of those. There are no conjunct forms or subjoined consonants.
This section maps Tai Dam consonant sounds to common graphemes in the Tai Viet orthography, grouped by high class ( h ), mid class ( m ), low class ( l ), and final consonant ( f ) types. Click on a grapheme to find other mentions on this page (links appear at the bottom of the page). Click on the character name to see examples and for detailed descriptions of the character(s) shown.
Sounds listed as 'infrequent' are allophones, or sounds used for foreign words, etc.
ꪝ [U+AA9D TAI VIET LETTER HIGH PO], eg. ꪝꪷ .
ꪜ [U+AA9C TAI VIET LETTER LOW PO], eg. ꪜꪳꪙ .
–ꪚ [U+AA9A TAI VIET LETTER LOW BO], eg. ꪛꪱꪜꪺ
–ꪚꪾ [U+AA9A TAI VIET LETTER LOW BO + U+AABE TAI VIET VOWEL AM], eg. ꪀꪚꪾ.
ꪔ [U+AA94 TAI VIET LETTER LOW TO], eg. ꪔꪰꪒ .
–ꪒ [U+AA92 TAI VIET LETTER LOW DO], eg. ꪭꪴꪒ .
ꪒ [U+AA92 TAI VIET LETTER LOW DO], eg. ꪼꪒ꫁ .
ꪁ [U+AA81 TAI VIET LETTER HIGH KO], eg. ꪁꪾ .
ꪀ [U+AA80 TAI VIET LETTER LOW KO], eg. ꪀꪚꪾ .
–ꪀ [U+AA80 TAI VIET LETTER LOW KO], eg. ꪮꪮꪀ .
ꪮ [U+AAAE TAI VIET LETTER LOW O], eg. ꪮ꪿ꪱꪉ .
–ꪀ [U+AA80 TAI VIET LETTER LOW KO], eg. ꪮꪮꪀ .
ꪎ [U+AA8E TAI VIET LETTER LOW SO], eg. ꪹꪎ .
ꪄ [U+AA84 TAI VIET LETTER LOW KHHO], eg. ꪶꪄꪙ .
ꪭ [U+AAAD TAI VIET LETTER HIGH HO], eg. ꪭꪴꪒ .
ꪬ [U+AAAC TAI VIET LETTER LOW HO], eg. ꪹꪬꪷꪉ .
ꪣ [U+AAA3 TAI VIET LETTER HIGH MO], eg. ꪣꪸ .
–ꪣ [U+AAA3 TAI VIET LETTER HIGH MO], eg. ꪹꪔꪸꪣ .
–ꪾ [U+AABE TAI VIET VOWEL AM in a diphone , eg. ꪁꪾ .
–ꪙ [U+AA99 TAI VIET LETTER HIGH NO], eg. ꪜꪳꪙ .
–ꪽ [U+AABD TAI VIET VOWEL AN] in a diphone, eg. ꪜ꫁ꪽ .
ꪐ [U+AA90 TAI VIET LETTER LOW NYO], eg. ꪻꪐ꪿ .
ꪉ [U+AA89 TAI VIET LETTER HIGH NGO], eg. ꪹꪉꪱ .
–ꪉ [U+AA89 TAI VIET LETTER HIGH NGO], eg. ꪮ꪿ꪱꪉ.
–ꪫ– [U+AAAB TAI VIET LETTER HIGH VO] (medial), eg. ꪵꪁꪫꪥ.
–ꪫ [U+AAAB TAI VIET LETTER HIGH VO], eg. ꪔꪲꪫ.
See also the diphthongs ending in w.
–ꪥ [U+AAA5 TAI VIET LETTER HIGH YO]
See also the diphthongs ending in j.
The Tai Viet Unicode block contains no characters with the general property symbol, however it contains 3 letters that act like symbols.
The first 2 symbols above are logograms. ꫛ [U+AADB TAI VIET SYMBOL KON] means person, and is used to distinguish between homophonous wordsb,9 such as ꫛ ꪶꪁꪙ
ꫜ [U+AADC TAI VIET SYMBOL NUENG] is a ligature for the word one. b,9
ꫝ [U+AADD TAI VIET SYMBOL SAM] indicates repetition of the previous word.
There are no native Tai Viet digits. ASCII digits are used.
Tai Viet text runs left to right in horizontal lines.
bidi_class properties for characters in the Tai Dam orthography described here.
This section brings together information about the following topics: writing styles; cursive text; context-based shaping; context-based positioning; baselines, line height, etc.; font styles; case & other character transforms.
You can experiment with examples using the Tai Viet character app.
The orthography has no case distinction, and no special transforms are needed to convert between characters.
The script has no context-sensitive shaping, however combining marks do need to be positioned relative to the shape of the base that they are combined with.
Glyph variants. The Tai Heritage Pro font also has font features that allow the following alternative glyph shapes for certain characters.
|feature||code point||alternative shapes|
|ꪊ [U+AA8A TAI VIET LETTER LOW CO]|
|ꪕ [U+AA95 TAI VIET LETTER HIGH TO]|
|ꪟ [U+AA9F TAI VIET LETTER HIGH PHO]|
|ꪻ [U+AABB TAI VIET VOWEL AUE]|
|꫞ [U+AADE TAI VIET SYMBOL HO HOI]|
Contextual positioning. Combining marks need to be positioned relative to the shape of the base that they are combined with. fig_vowp shows an example: the combining marks are higher to the right than the left, because of the size of the glyphs below.
Location of combining marks. The Tai Heritage Pro font offers a variant feature that allows placement of combining vowel signs and tones over the onset consonant, or over the final consonant in a closed syllable, see fig_vowp. The underlying sequence of code points is identical.
Whereas the code point sequence remains the same for the example just shown, the same font feature can also be used to support a different code point sequence for ꪾ [U+AABE TAI VIET VOWEL AM]. By default, the code point order for the left-hand example in fig_vowp1 would be:
ꪊꪚꪾ [U+AA8A TAI VIET LETTER LOW CO + U+AA9A TAI VIET LETTER LOW BO + U+AABE TAI VIET VOWEL AM]
With the vowp feature set to 1, combining marks appear over the onset, except for this specific combination. This means that you can use the code point sequence:
ꪊꪾꪚ [U+AA8A TAI VIET LETTER LOW CO + U+AABE TAI VIET VOWEL AM + U+AA9A TAI VIET LETTER LOW BO]
Tai Viet has syllables that include free-standing vowel signs before and/or after the base, eg. ꪹꪉꪱ Tai Viet users do not expect these to be connected to the onset consonant. When a cursor moves across text, they expect it to stop before and after each of these characters, and not skip the complete syllable. All spacing characters behave this way.
Unlike many other Tai scripts, Tai Viet uses spaces between words.b However, this is a fairly recent innovation.
Brase provides some algorithmic detail for handling older texts without spacing.btd
, [U+002C COMMA]
. [U+002E FULL STOP]
꫞ [U+AADE TAI VIET SYMBOL HO HOI]
Observation: The UDHR text contains regular ASCII punctuation, including commas, periods, and colons, as well as dashes to separate text. Some examples can be seen in the sample text at the start of this page.
Poems & songs. The only punctuation in the Unicode Tai Viet block is for poems and songs: ꫞ [U+AADE TAI VIET SYMBOL HO HOI] marks the beginning and ꫟ [U+AADF TAI VIET SYMBOL KOI KOI] marks the end of the text.
Tai Dam commonly uses ASCII parentheses to insert parenthetical information into text.
( [U+0028 LEFT PARENTHESIS]
) [U+0029 RIGHT PARENTHESIS]
Repetition. ꫝ [U+AADD TAI VIET SYMBOL SAM] indicates repetition of the previous word.
Observation: The primary break point for text seen online is the inter-word space.
Show (default) line-breaking properties for characters in the Tai Dam orthography.
This section looks at ways in which spacing is applied between characters over and above that which is introduced during justification.
Tai Viet uses the so-called 'alphabetic' baseline, which is the same as for Latin and many other scripts.
This section is for any features that are specific to Tai Viet and that relate to the following topics: general page layout & progression; grids & tables; notes, footnotes, etc; forms & user interaction; page numbering, running headers, etc.