Tai Dam

Letters

Combining marks

Punctuation

Other

Vowel sounds

Consonant sounds

	labial	alveolar	post- alveolar	palatal	velar	glottal
stop	p b	t d			k ɡ	ʔ
aspirated		tʰ
affricate			t͡ɕ
fricative	f v	s			x	h
nasal	m	n		ɲ	ŋ
approximant	w	l		j
trill/flap		r

r and ɡ are used in Vietnamese names.

Tone

tbd

Structure

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 LETTER LOW BO + U+AABE 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.

Vowel summary table

The following table summarises the main vowel to character assigments.

For additional details see vowel_mappings.

Post-consonant vowels

Vowels are written using a mixture of 13 ordinary spacing characters (of which 5 are also consonants) and 7 combining marks. 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.

This page lists 6 multipart vowels, made from 6 vowel signs and 3 consonants. Multipart vowels can involve up to 3 glyphs, though usually only 2, and glyphs can surround the base consonant(s) on 2 sides. There are 5 pre-base vowel glyphs (all letters), but no circumgraphs.

Pre-base vowel signs

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.

ꪹ␣ꪶ␣ꪵ␣ꪻ␣ꪼ

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:

ꪵꪣꪫ

Note that ꪵ should not be typed as two successive ꪹ 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.

show composition

ꪵꪁꪫꪥ

Standalone vowels

There are no independent vowels, and Tai Viet represents what look like standalone vowels using a vowel sign attached to ꪮ or ꪯ, and phonetic transcriptions include an initial glottal stop.

ꪮ꪿ꪱꪉ

ꪵꪮꪚ

Tones

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.

Vowel sounds to characters

Consonant summary table

The following table summarises the main consonant to character assigments.

For initial consonants, the left column shows high class consonants, and the right low class.

For additional details see consonant_mappings.

Basic consonants

The letters ʰ and ˡ below each character indicate whether the class is high or low.

Other dialects

Onsets

The consonant wa can appear immediately after the initial consonant in a syllable. It is written using ꪫ.

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 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

Finals

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

Consonant clusters occur in the following circumstances:

• When an initial consonant is labialised, see onsets.
• Where a syllable ends with a consonant and another syllable begins.

No special characters or viramas are involved, in any of those. There are no conjunct forms or subjoined consonants.

Consonant sounds to characters

Font styles

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
lcoa	ꪊ
htoa	ꪕ
hpho	ꪟ
auea	ꪻ
hoia	꫞

Context-based shaping & positioning

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 AABE. By default, the code point order for the left-hand example in fig_vowp1 would be:

ꪊꪚꪾ

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

Word boundaries

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

Graphemes

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.

Phrase & section boundaries

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: ꫞ marks the beginning and ꫟ marks the end of the text.

Bracketed text

(␣)

Tai Dam commonly uses ASCII parentheses to insert parenthetical information into text.

	start	end
standard	(	)

Abbreviation, ellipsis & repetition

Repetition. ꫝ indicates repetition of the previous word.

Line breaking & hyphenation

tbd

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.

Baselines, line height, etc.

tbd

Tai Viet uses the so-called 'alphabetic' baseline, which is the same as for Latin and many other scripts.