Tai Viet, Tai Dam

Notable features

• tone notation is based on a complete set of duplicate consonants for high and low tone
• tone can be indicated using either diacritics or letters
• most native words are monosyllabic
• vowels are indicated using both combining marks and letters
• Tai Viet uses visual placement: vowel glyphs to the left of the base are standalone letters
• there are no independent vowels

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
	img

r and ɡ are used in Vietnamese names.

Tone

The Tai Dam language has 6 tones: 3 level pitch tones, and 3 contour tones.

The 2nd and 5th tones are the only tones used in checked syllables, but they can also appear in unchecked syllables, too.

See how tones are written.

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

Syllables follow the pattern C (w) V (C)

Syllable onsets are normally simple, but may have a medial -w-.

Syllable codas include -p -t -k -ʔ, which create 'checked' syllables, and otherwise -m, -n, -ŋ, as well as the glides -j, -w.

Post-consonant vowels

None of the combining marks are spacing marks (meaning that none of them consume horizontal space when added to a base consonant).

Pre-base vowel signs

Five CV combinations are written using vowel signs that appear to the left of the onset consonant.

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.

eg.

ꪵꪣꪫ

ꪵ,ꪣ,ꪫ

In fact, these vowel signs are placed before the start of the syllable onset. This means that in a word that begins with more than one consonant letter (ie. in labialised consonants) 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 actually pronounced.

fig_prebase shows an example to graphically illustrate the relationships between the characters.

show composition

ꪵꪁꪫꪥ

Standalone vowels

Vowels in Tai Dam are always preceded by a consonant, but that consonant may be a glottal stop, written using ꪮ or ꪯ followed by the relevant vowel sign(s). There are no independent vowels.

ꪮꪲꪒ

ꪮ꪿ꪱꪉ

ꪵꪮꪚ

Tones

See also tone.

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.

Vietnam The Tai community in Vietnam developed an approach where tone is marked by ordinary spacing characters that are typed and stored after all other elements in the syllable.

Diaspora 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 following illustrates the different positioning for diacritic and letter tone marks, used for the same word, pɔm˦ apple.

Mapping tones & characters The following chart shows how to tell which tones are associated with a syllable.

Vowel sounds to characters

Basic consonants

Basic consonant sounds in Tai Dam are written using the following letters.

Click on each letter for more details and for examples of usage, especially where more than one sound is indicated.

low

high

Other dialects

Onsets

Tai Dam labialises an initial velar consonant in some syllables, but doesn't otherwise have consonant clusters in syllable onsets. The labialisation is indicated using the ordinary letter ꪫ; there are no dedicated medial consonants.

ꪁꪫꪱꪣ

ꪄꪷꪄꪫ꪿ꪱ

The pronunciation of a consonant followed by VO can be ambiguous if there is no diacritic present and the vowel sign appears before the base. For example, the following does not involve labialisation:

ꪵꪄꪫ

The following pairs illustrate how a vowel sign or a tone diacritic can resolve the ambiguity.

ꪀꪲꪫ ḵiw

ꪀꪫꪲ ḵwi

ꪵꪀ꫁ꪫ ɛḵ²w kɛw

ꪵꪀꪫ꫁ ɛḵw² kʷɛ

In order to address the ambiguity when no diacritic is present, the character ꪥ may be appended to the end of the sequence, indicating labialisation.

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

Codas

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, Tai Dam has ways of writing several rhymes, where a vowel sign represents a vowel sound followed by a final consonant. See vowels. These include:

Consonant sounds to characters

Font styles

Glyph variants. The Tai Heritage Pro font 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. Polysyllabic words may be written without space between the syllables.u

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.

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.

Dashes. Dashes are used to separate phrases.

Poems & songs. The only native 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.

fig_baselines shows glyphs from the Tai Heritage Pro font. Tai Viet extenders and combining marks, extend well beyond the Latin ascenders and descenders, creating a need for much larger line heights.