Lao script summary

Updated 14 April, 2019 • tags lao, scriptnotes

This page provides basic information about the Lao script, and its use for the Lao language. It is not authoritative, peer-reviewed information – these are just notes I have gathered or copied from various places as i learned. For character-specific details follow the links to the Lao character notes.

For similar information related to other scripts, see the Script comparison table.

Clicking on red text examples, or highlighting part of the sample text shows a list of characters, with links to more details. Click on the vertical blue bar (bottom right) to change font settings for the sample text. Colours and annotations on panels listing characters are relevant to their use for the Template language.

Sample (Lao)

ມາດຕາ 1: ມະນຸດເກີດມາມີສິດເສລີພາບ ແລະ ສະເໝີໜ້າກັນໃນທາງກຽດຕິສັກ ແລະ ທາງສິດດ້ວຍມະນຸດມີສະຕິສຳປັດຊັນຍະ(ຮູ້ດີຮູ້ຊົ່ວ)ແລະມີມະໂນທຳຈື່ງຕ້ອງປະພຶດຕົນຕໍ່ກັນໃນທາງພີ່ນ້ອງ.

ມາດຕາ 2: ຂໍ້ 1.ຄົນຜູ້ໃດກໍ່ອ້າງຕົນໄດ້ວ່າ:ມີສິດ ແລະ ເສລີພາບທຸກຢ່າງທີ່ໄດ້ປ່າວຮ້ອງຢູ່ໃນປະກາດສະບັບນີ້ໂດຍບໍ່ເລືອກໜ້າ ບໍ່ຈຳກັດເຊື້ອຊາດ,ຜິວເນື້ອ,ເພດ,ສາສະໜາ ຄວາມຄິດເຫັນໃນດ້ານການເມືອງ ຫຼື ອື່ນໆ ກຳເນີດແຫ່ງຊາດຫຼື ສັງຄົມຖານະການມີຊັບສົມບັດມາກ ຫຼື ນ້ອຍ,ມີຕະກຸນ ຫຼື ຖານະອື່ນໆ. ຂໍ້ 2.ອີກປະການໜື່ງ ຈະບໍ່ຈຳກັດຢ່າງໃດໃນການແຕກຕ່າງກັນອັນເນື່ອງມາຈາກລະບຽບການເມືອງການປົກຄອງ ຫຼື ລະຫວ່າງຊາດຂອງປະເທດ ຫຼື ດິນແດນ ຊື່ງບຸກຄົນຜູ້ໃດຜູ້ໜື່ງສັງກັດຢູ່;ດິນແດນນັ້ນຈຳເປັນເອກະລາດຢູ່ໃນຄວາມອາລັກຂາຂອງມະຫາອຳນາດ ຫຼື ບໍ່ມີອິດສະຫຼະ ຫຼື ຖືກລົດອະທິປະໄຕລົງໂດຍຈຳກັດກໍ່ຕາມ.

Usage & history

From Scriptsource:

The Lao script is used for writing the Lao language, and is also the official script of a number of minority languages in Laos. The Lao language is closely related to Thai; there is a considerable Lao-speaking population in Thailand who write their language with the Thai script. However, the Lao script underwent a number of reforms which caused significant divergence from the Thai script. When the communist Pathet Lao overthrew the Lao government in 1975, they implemented a final spelling reform which simplified and standardized the script.

From Wikipedia:

Lao script, or Akson Lao, (Lao: ອັກສອນລາວ [ʔáksɔ̌ːn láːw]) is the primary script used to write the Lao language and other minority languages in Laos. It was also used to write the Isan language, but was replaced by the Thai script.

The Lao alphabet was adapted from the Khmer script, which itself was derived from the Pallava script, a variant of the Grantha alphabet descended from the Brahmi script, which was used in southern India and South East Asia during the 5th and 6th centuries AD. Akson Lao is a sister system to the Thai script, with which it shares many similarities and roots. However, Lao has fewer characters and is formed in a more curvilinear fashion than Thai.

Distinctive features

Lao is an alphabet. This means that it is phonetic in nature, where each letter represents a basic sound. See the table to the right for a brief overview of features, taken from the Script Comparison Table.

The script was originally an abugida, but since the script reforms leading up to 1960 it has been alphabetic. The syllable is the unit for various aspects of the behaviour of the script. Lao is a tonal language, and the script is designed to reflect tonal information.

The alphabet is split into vowels and consonants. The consonants are grouped into classes that affect the default tonal behaviour of a syllable. There are no independent vowels. Where there is no consonant to support a vowel sign, the character [U+0EAD LAO LETTER O] is used as a support. Vowel signs are typically used in combinations to form the vowel sounds of a syllable.

Lao has only one subjoined consonant, used in combination only with HA (see below). It doesn't have any code points dedicated to medial or final consonants, although consonants do appear in those positions.

Character lists

The Lao script characters in Unicode 11.0 are in the following block:

Follow these links for information about characters used by languages associated with this script. The numbers in parentheses are for non-ASCII characters.

For character-specific details see Lao character notes.

Structure

The syllable is a basic element of the Lao language, and many words are monosyllabic. All syllables begin with a written consonant. Syllables that begin with a vowel sound are written with a silent base consonant.

The phonological structure of a syllable is (C)w?V(C), using the following:

OnsetVowelFinal
p pʰ b t tʰ tʷʰ d tɕ tɕʷ k kʷ kʰ kʷʰ ʔ ʔʷ i iː ɯ ɯː u uː p t k ʔ
f s sʷ h e eː ɤ ɤː o oː  
m n ɲ ŋ ŋʷ ɛ ɛː a aː ɔ ɔː m n ŋ
l lʷ j w iə̯ iːə̯ ɯə̯ ɯːə̯ uə̯ uːə̯ w j

ʔ occurs after short vowels.

Unlike Thai, its close neighbour linguistically, Lao doesn't naturally support onset clusters of consonants other than with w, and then not before rounded vowels. w

Lao also has 6 phonological tones in unchecked syllables (ie. ending in a vowel, or m, n, ŋ, w or j), and 4 in checked syllables (ie. ending in p, t, k, or ʔ).

Name Vowel Final Unchecked? Checked?
Rising ˨˦ or ˨˩˦ ě  
High ˦ é
High falling ˥˧ ê  
Mid ˧ ē
Low ˩ è
Low falling ˧˩ e᷆

See the section Tone values for more detailed discussion of tones.

In yellow boxes, show:

Text direction

Lao text runs left to right in horizontal lines.

Vowels

Inherent vowel

Unlike its close neighbour, Thai, consonants do not carry an inherent vowel. The vowel a has to be written explicitly in Lao.

Vowel absence

Vowel absence after syllable-final consonants is not normally marked in any way. Nor is it marked in syllable-initial clusters.

Vowel signs

To produce a different vowel than the inherent one, Lao uses one or more vowel-signs, eg. ກິ ki.

Vowel signs in Lao are a mixture of combining characters and ordinary spacing characters. Only the superscript and subscript vowel-signs are combining characters.

Vowel-signs can also be combined to create additional sounds.

Prescript vowel-signs

ເ␣ແ␣ໂ␣ໄ␣ໃ

Of the vowel-signs, 5 appear to the left of the onset consonant.

Like Thai, Lao uses a visual encoding model, so these characters are not combining characters, and are typed and stored before the base.

Note that [U+0EC1 LAO VOWEL SIGN EI] should not be typed as two successive [U+0EC0 LAO VOWEL SIGN E] characters.

Other vowel-signs

າ␣ະ␣ັ␣ິ␣ີ␣ຶ␣ື␣ຸ␣ູ␣ຽ␣ໍ␣ົ␣ຳ

[U+0EB0 LAO VOWEL SIGN A], [U+0EB2 LAO VOWEL SIGN AA], and [U+0EBD LAO SEMIVOWEL SIGN NYO] are normal spacing characters; the rest are combining characters.

[U+0EB3 LAO VOWEL SIGN AM] is classed as a vowel, but also contains the final consonant m, represented by a built-in nikhahit (cf. -ໍ [U+0ECD LAO NIGGAHITA​]). It is a spacing combining character.

[U+0EBD LAO SEMIVOWEL SIGN NYO] was originally an alternate form of non-initial [U+0E8D LAO LETTER NYO], but is now used for diphthongs. 

Consonants pronounced as vowels

ອ␣ວ

The consonant [U+0EAD LAO LETTER O] is also pronounced as the vowel ɔː when it appears alone in a closed syllable.

Unlike Thai, it seems that [U+0EA7 LAO LETTER WO] doesn't act as a consonant in its own right.

Both of these characters also appear as a part of the complex vowels described below.

Vowel-sign combinations

The various vowel-signs described just above can be mixed together with [U+0EAD LAO LETTER O], [U+0E8D LAO LETTER NYO], [U+0EA7 LAO LETTER WO], and [U+0EBD LAO SEMIVOWEL SIGN NYO] to produce additional sounds, as shown in the examples below.

-ັຍ␣-ັອ␣-ັຽ␣-ົວ␣-ິວ␣-ີວ␣-າຍ␣-າຽ␣ເ-ິ␣ເ-ີ␣ເ-ັ␣ເ-ະ␣ແ-ະ␣ເ-ຍ␣ແ-ັ␣ແ-ວ␣ໂ-ະ␣-ຽວ␣-ົວະ␣ເ-ົາ␣ເ-ັຍ␣ເ-ຶອ␣ເ-ືອ␣ເ-າະ␣ເ-ັຍະ␣ເ-ັຽວ

Vowel-sign placement

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. Numbers after + sign indicate multiple code points.

At maximum, vowel components can occur concurrently on 3 sides of the base.

Distribution of vowel elements is as follows:

-ັ -ິ -ີ -ຶ -ື -ໍ -ົ -ຳ
ເ ແ ໂ ໃ ໄ ະ າ ອ ວ ຍ ຽ ຍ ຽ ະ ວ
  -ຸ -ູ    

Standalone vowels

Standalone vowels are not preceded by a consonant, and may appear at the beginning or in the middle of a word. This typically includes a way to represent the sound of the inherent vowel in isolation.

Lao uses a silent [U+0EAD LAO LETTER O] as a base, to which vowel signs are applied, eg. ໂອ ōʔ (ō) bowl.

Lao has no independent vowel letters.

Consonants

Each consonant is associated with a high, mid, or low class related to tone values. (Low class consonants are indicated using an underline in the transliteration. The consonants that default to mid class have an inverted breve below the transliteration.)

High class consonants

ຂ␣ຖ␣ຜ␣ຫ␣ສ␣ຝ

A silent [U+0EAB LAO LETTER HO SUNG] can be added before the following characters to make their default tonal class high:

ງ␣ນ␣ມ␣ລ␣ວ␣ຍ␣ຽ

See syllable_onset for further details about how these are presented.

Mid class consonants

ກ␣ຈ␣ຕ␣ດ␣ປ␣ບ␣ຢ␣ອ

[U+0EAD LAO LETTER O] is silent when used as a base for vowels at the beginning of a syllable. When it appears alone after a base consonant it becomes the vowel ɔː, eg. ໂອ ōʔ òː bowl. It is also used in combination with other characters to produce additional vowel sounds (see below).

Low class consonants

ຄ␣ງ␣ຍ␣ທ␣ນ␣ພ␣ມ␣ລ␣ຣ␣ວ␣ຮ␣ຊ␣ຟ

Syllable-onset clusters

Unlike Thai, Lao doesn't have syllable-initial clusters other than the clusters associated with tone (described in the previous section), and consonants followed by [U+0EA7 LAO LETTER WO] and a non-rounded vowel, eg. ຄວາຍ ḵʰw̱āɲ̱ (khwāi) buffalo.

There are alternate forms for some of the tone-related compounds mentioned in consonant_class. Two can be represented as ligatures, for which there are separate characters in Unicode: [U+0EDC LAO HO NO] and [U+0EDD LAO HO MO]. Another can be represented by converting the second consonant to a subscript (ຫຼ), also available as a separate character in Unicode. d462 u378

ໜ␣ໝ␣ຼ

In a consonant cluster any tone marks or superscript vowels appear over the second consonant.

Syllable-final consonants

Lao doesn't have any code points dedicated to syllable final consonants, although consonants do appear in those positions, eg. ນົກ ṉok̯ bird.

Only the following consonants appear in syllable-final position. Note how the sound may change.

ກ␣ງ␣ຍ␣ດ␣ນ␣ບ␣ມ␣ຢ␣ຣ␣ວ

Because Lao requires vowels to be written, there is not the ambiguity about syllable boundaries that one finds in Thai caused by doubts about whether a consonant is syllable-final or a syllable in its own right.

A final m sound may be represented by   [U+0EB3 LAO VOWEL SIGN AM].

Consonant clusters

Consonant clusters occur in the following circumstances:

No special characters or viramas are involved, except that (as described in syllable_onset:

Tones

່␣້␣໊␣໋

The expected typing and storage position for tone marks is immediately after the base consonant of the syllable, or after a superscript vowel-sign if there is one. However, the tone mark should be typed before [U+0EB3 LAO VOWEL SIGN AM], and should be displayed above the nikhahit, eg. ກ່ຳ.

Experts disagree on the number and nature of tones in the various dialects of Lao. According to some, most dialects of Lao and Isan have six tones, those of Luang Prabang have five. wl See the section tonevalues for more detailed discussion of tones.

Other letters

Two more characters have the general category of letter.

ຯ␣ໆ

[U+0EAF LAO ELLIPSIS] is used to indicate ellipsis or abbreviation.

[U+0EC6 LAO KO LA] is used to indicate repetition of preceding sound. It's also used in ໆລໆ kʰɯaŋ-mǎːj-lɛ-ɯːn-ɯːn (ເຄຶ່ອງໝາຍ ແລະອຶ່ນໆ), with a meaning similar to etc.

Unicode 6.1 added 2 consonant letters for Khmu.

ໞ␣ໟ

Unicode 12 added 14 consonant letters and 1 combining mark for writing Pali.

ຆ␣ຉ␣ຌ␣ຎ␣ຏ␣ຐ␣ຑ␣ຒ␣ຓ␣ຘ␣ຠ␣ຨ␣ຩ␣ຬ␣຺

Combining marks

Apart from those already described in the sections relating to vowel-signs and tones, there is only one combining mark in the Lao Unicode block: [U+0ECC LAO CANCELLATION MARK].

See also otherletters for a Pali virama.

Punctuation

The Lao Unicode block contains no punctuation. Lao uses western punctuation. See phrase.

Numbers, dates, currency, etc.

Lao uses Western digits.

There is, however, a set of Lao digits.

໐␣໑␣໒␣໓␣໔␣໕␣໖␣໗␣໘␣໙

Glyph shaping & positioning

Prescript vowels are visually ordered, and therefore do not need to be positioned by the font.

Vowel-signs, tones, and one consonant, however, have combining characters that need to be correctly positioned relative to the base character, and can be combined with a single base character.

None of the characters, however, requires shaping based on the visual context.

Structural boundaries & markers

Word boundaries

Words are not separated by spaces.

Double-clicking or other selection methods are expected to identify word boundaries. For this, an application needs to use a dictionary to parse the text.

Phrase boundaries

Spaces are used, but represent phrase or sentence boundaries. Western punctuation is also used.

Quotations

According to CLDR, the default quote marks for Lao are [U+201C LEFT DOUBLE QUOTATION MARK] at the start, and [U+201D RIGHT DOUBLE QUOTATION MARK] at the end.

When an additional quote is embedded within the first, the quote marks are [U+2018 LEFT SINGLE QUOTATION MARK] and [U+2019 RIGHT SINGLE QUOTATION MARK].

Line & paragraph layout

Text direction

Lao is written horizontally and left to right.

Line-breaking

Although Lao doesn't use spaces or dividers between words, the expectation is that line-breaks occur at word boundaries.

Unlike Thai or Khmer, it is fairly straightforward to parse individual syllables in Lao, because its alphabetic nature makes it possible to identify syllable-final consonants. (Note that syllable wrapping must include any syllable-initial clusters involving h or l.)

While nearly all syllables can be argued to be words in their own right, there is still a preference for keeping multi-syllabic words (eg. ປະເທດ p̯aēṯʰd̯ (pa thēt) country) together when wrapping text to the next line. For this, an application typically needs to use a dictionary to parse Lao text.

However, widely used software automatically inserts [U+200B ZERO WIDTH SPACE] (ZWSP) in Lao text at word or syllable boundaries, and many web pages use such inserted ZWSP characters to get browsers to wrap correctly. g

If a dictionary fails to keep two or more syllables together as needed, it should be possible to use the Unicode character U+2060 WORD JOINERbetween the two syllables. This is an invisible character, equivalent to a zero-width no-break space, and used to prevent line-breaks.

Text alignment & justification

Since spaces aren't used to separate words, Lao has to use alternative strategies for justification of text.

Use the control below to see how your browser justifies the text sample here.

ບຸກຄົນສະເໝີກັນຕໍ່ໜ້າກົດໝາຍ ແລະ ມີສິດທີ່ຈະໄດ້ຮັບຄວາມຄຸ້ມຄອງຂອງກົດໝາຍເທົ່າທຽມກັນໂດຍບໍ່ມີການແຕກຕ່າງທຸກຄົນມີສິດທີ່ຈະໄດ້ຮັບຄວາມຄຸ້ມຄອງເທົ່າທຽມກັນຕໍ່ການກະທຳໃດໆທີ່ຖືກບຸກຄົນແຕກຕ່າງກັນອັນອາດເປັນການລະເມີດໃບປະກາດສະບັບນີ້ ແລະ ຕໍ່ການທ້າທາຍໃດໆທີ່ຈະຖືໃຫ້ແຕກຕ່າງກັນດັ່ງນີ້:

Counter styles

Lao uses one native, numeric counter style, according to the document Ready-made Counter Styles. The style uses the Lao digits: '໐' '໑' '໒' '໓' '໔' '໕' '໖' '໗' '໘' '໙''.

1 ⇨  2 ⇨  3 ⇨  4 ⇨  11 ⇨ ໑໑ 22 ⇨ ໒໒ 33 ⇨ ໓໓ 44 ⇨ ໔໔ 111 ⇨ ໑໑໑ 2222 ⇨ ໒໒໒

Numbers produced by the Lao counter style.

You can experiment with these styles using the Counter styles converter.

TBD

Further information needed for this section includes:

Glyph shaping & positioning
    Cursive text
    Context-based shaping
    Multiple combining characters
    Context-based positioning
    Transforming characters

Structural boundaries & markers
    Grapheme, word & phrase boundaries
    Hyphens & dashes
    Bracketing information
    Quotations
    Abbreviations, ellipsis, & repetition
    Emphasis & highlights
    Inline notes & annotations

Inline layout
    Inline text spacing
    Bidirectional text

Line & paragraph layout
    Hyphenation
    Text alignment & justification
    Counters, lists, etc.
    Styling initials
    Baselines & inline alignment

Page & book layout
    General page layout & progression
    Directional layout features
	Grids & tables
    Notes, footnotes, etc.
    Forms & user interaction
    Page numbering, running headers, etc.

Tone values

The tone depends on the class of the initial consonant in a syllable, the structure of the syllable, and whether or not a tone mark is applied to override the default. Tone values vary depending on location in Laos. There is some disagreement whether there are 5 or 6 tones in Vientiane, and you will see in the tables below that different sources disagree on the tones produced.

The following tables present different descriptions of tone values in Lao for the Vientiane dialect. The first and third tables basically agree on the tone value, although the names of tones vary. The middle table shows some different tone values altogether. See a list of studies for Vientiane tones.

This diagram shows 5 tones with names corresponding to a mixture of the first two tables below.

Diagrams of tone vectors.

Tone marks are normally used only on open syllables, and modify the default tone value. Two of the four tone marks are only used with Class 1 consonants. Tone marks tend to be placed directly over the consonant (or superscript vowel), unlike Thai which tends to place them slightly to the right.

Open or live syllables are those that end with a long vowel or sonorant (eg. ງນມຍວ). Closed or dead syllables end with a stop consonant (eg. ກດບ) or short vowel.

  Open Closed
short vowel
Closed
long vowel
Tone
mai eːk
Tone
mai toː
Tone
mai tiː
Tone
mai cat-ta-waː
Class 1 low ˊ high ˆ low falling ˉ mid ˋ high falling ˋ high falling ˇ low rising
Class 2 ˇ low rising ˊ high ˆ low falling ˉ mid ˆ low falling - -
Class3 ˊ high ˉ mid ˋ high falling ˉ mid ˋ high falling - -

Refs: Daniels

  Live Dead
short vowel
Dead
long vowel
Tone
mai eːk
Tone
mai toː
Tone
mai tiː
Tone
mai cat-ta-waː
Class 1 ˋ low ˇ rising ˇ rising mid ˆ falling ˊ high ˇ rising
Class 2 ˇ rising ˇ rising ˋ low mid ˋ low - -
Class3 ˊ high mid ˆ falling mid ˆ falling - -

Refs: Simmala

  Live Dead
short vowel
Dead
long vowel
Tone
mai eːk
Tone
mai toː
Tone
mai tiː
Tone
mai cat-ta-waː
Class 1 low rising high rising low falling high-mid high falling    
Class 2 low rising high rising low falling high-mid low falling    
Class3 high rising high-mid high falling high-mid high falling    

Refs: SEAlang

The Simmala chart seems suspect to me, since they say in the text that the rising tone doesn't occur in dead syllables, and the book has examples of dead syllables with long vowels with a low tone.

References

  1. [ s ] Buasawan Simmala & Benjawan Poomsan Becker, Lao for Beginners , ISBN 1-887521-28-3
  2. [ d ] Peter T. Daniels & William Bright, The World's Writing Systems, ISBN 0-19-507993-0.
  3. [ u ] The Unicode Standard v5.0, esp the South Asian scripts chapter.
  4. [ w ] Wikipedia, Lao language
  5. [ wh ] Wikipedia Help, IPA/Thai and Lao
  6. [ lg ] W3C Southeast Asian task force, Lao Gap Analysis
  7. [ g ] W3C Southeast Asian task force, Github discussion list
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