Lao

Orthographic development & variants

The script was originally an abugida, but since the script reforms leading up to 1960 it has been alphabetic. When the communist Pathet Lao overthrew the Lao government in 1975, they implemented a final spelling reform which simplified and standardized the script.

Letters

Combining marks

Numbers

Punctuation

Symbols

Other

Vowel sounds

Consonant sounds

Initials

	labial	alveolar	post- alveolar	palatal	velar	glottal
stops	p b	t d			k	ʔ
aspirated	pʰ	tʰ			kʰ
affricates			t͡ɕ
fricatives	f	s			x	h
nasals	m	n		ɲ	ŋ
approximants	ʋ/w	l		j
trills/flaps		r

Tone

Lao has 6 phonological tones in unchecked syllables, and 4 in checked syllables.

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 about whether there are 5 or 6 tones in Vientiane, and the tables below show that different sources disagree on the tones produced. According to some, most dialects of Lao and Isan have six tones, those of Luang Prabang have five.wl

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).

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.wl,#Syllables Onset consonants followed by labialisation include: tʷʰ tɕʷ kʷ kʷʰ ʔʷ sʷ ŋʷ lʷ.

Only a small set of consonants occur at the end of a syllable. ʔ occurs after short vowels.

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).

Vowel summary table

The following table summarises the main vowel to character assigments.

The diphthongs section below contains one character that incorporates a final nasal. The list doesn't include those combinations that involve simply appending a glide after the vowel (see compositeV). Standalone vowels use the character shown as a base for the normal vowel symbols. ◌ indicates the location of consonants, but doesn't necessarily indicate the presence of a combining mark.

For more details see vowel_mappings.

Vowel signs A & MAI KAN

ກະ ka U+0E81 LAO LETTER KO + U+0EB0 LAO VOWEL SIGN A

The short vowel a has to be written explicitly, using 0EB0 in open syllables, and   0EB1 in closed syllables. The following word shows examples of both.

ລະດັບ

When used in conjunction with other vowels, 0EB0 and   0EB1 are also used to indicate short vowels for open and closed syllables, respectively. In phonetic transcriptions, shortened open vowels often end with a glottal stop. For example, compare:

ໂຕະ

ໂຕ

See also vlength.

Vowels following consonants

Unlike its close relative, Thai, the Lao orthography is an alphabet and has no inherent vowel. It represents vowels using combining marks, dedicated vowel letters, and a couple of consonants, much of the time grouped together in various combinations. This page lists 28 composite vowels, which can involve up to 4 glyphs, and can surround the base consonant(s) on up to 3 sides simultaneously.

Vowels are often written differently when they appear in a closed vs. open syllable.

Lao uses visual placement: only the 8 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.

There are 5 pre-base letters. There are no single-character circumgraphs in Lao text, but a single vowel or diphthong is frequently made up of multiple components, some of which will appear on different sides of the base consonant(s).

None of the marks are spacing combining marks; the spacing glyphs used to write vowels are all letters.

Pre-base vowel signs

ໂກ koː U+0EC2 LAO VOWEL SIGN O + U+0E81 LAO LETTER KO

Five vowel signs appear to the left of the onset consonant. See an example in fig_prebase.

ເ◌␣ແ◌␣ໂ◌␣ ␣ໄ◌␣ໃ◌

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

ແມວ

Note that ແ should not be typed as two successive ເ 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 (such as for shifting the tone) 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. Tone marks and post-base vowel signs are however attached to the latter. For the following examples, click on the Lao text to see the order of characters.

ໃຫຍ່ ເຫຼືອງ

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

show composition

ແກວ່ງ

Composite vowels

ເກຶອ kuːə U+0EC0 VOWEL SIGN E + U+0E81 LETTER KO + U+0EB6 VOWEL SIGN Y + U+0EAD LETTER O

In the lists below, ◌ represents a consonant. Vowels used in closed syllables are indicated by a trailing ◌, or a trailing hyphen in the IPA transcription.

Lao has many vowel sounds that are represented by more than one code point. Composite vowels can involve up to 4 glyphs, and glyphs can surround the base consonant(s) on up to 3 sides.

show composition

ເຈັ້ຍ

Some composite vowels represent plain vowel sounds:

ເ◌ະ␣ເ◌ັ␣ເ◌ິ␣ເ◌ີ␣ໂ◌ະ␣ແ◌ະ␣ແ◌ັ␣ເ◌າະ␣ັອ

The other composites represent diphthongs, which generally end in one of ə̯, i, or w.

In some cases, the spelling is straightforward because a semivowel simply follows a plain vowel.

ິວ␣ີວ␣ຽວ␣ເີ◌ຽ␣ເີ◌ຍ␣ແ◌ວ␣ອຍ␣ັຍ␣າຍ␣າຽ␣າວ

For others, the spelling doesn't closely follow the sound represented.

ັຽ␣ເ◌ັຍ␣ເ◌ຍ␣ເ◌ຶອ␣ເ◌ືອ␣ັວ␣ົວະ␣ົວ␣ວາ␣ເ◌ົາ

Observation: Simmala et al. list the composite vowel ເ-ັຍະ for -ia in (only) one location, but I have yet to identify words containing this sequence, and suspect that it may be a typographic error.

Characters that don't appear in the combinations:

◌ຸ␣◌ູ␣ໃ◌␣ໄ◌␣◌ໍ␣◌ຳ

Show which combinations contain a given character:

ິ	ເ◌ິ␣ ␣ິວ
ີ	ເ◌ີ␣ ␣ເ◌ີຽ␣ເ◌ີຍ␣ ␣ີວ
ຶ	ເ◌ຶອ
ື	ເ◌ືອ
ເ	ເ◌ະ␣ເ◌ັ␣ເ◌ິ␣ເ◌ີ␣ເ◌າະ␣ ␣ເ◌ີຽ␣ເ◌ີຍ␣ເ◌ົາ␣ ␣ເ◌ັຍ␣ເ◌ຍ␣ເ◌ັຍະ␣ເ◌ຶອ␣ເ◌ືອ
ແ	ແ◌ະ␣ແ◌ັ␣ ␣ແ◌ວ
ໂ	ໂ◌ະ
ະ	ເ◌ະ␣ໂ◌ະ␣ແ◌ະ␣ເ◌າະ␣ ␣ເ◌ັຍະ␣ົວະ
ັ	ເ◌ັ␣ແ◌ັ␣ັອ␣ ␣ັຍ␣ ␣ັຽ␣ເ◌ັຍ␣ເ◌ັຍະ␣ັວ
າ	ວາ␣ ␣ເ◌າະ␣ ␣າຍ␣າຽ␣າວ␣ເ◌ົາ
ົ	ົວະ␣ົວ␣␣ເ◌ົາ
ອ	ເ◌ຶອ␣ເ◌ືອ␣ັອ␣ ␣ອຍ
ຽ	ຽວ␣ເ◌ີຽ␣າຽ␣ ␣ັຽ
ຍ	ເ◌ີຍ␣ອຍ␣ັຍ␣າຍ␣ ␣ເ◌ັຍ␣ເ◌ຍ␣ເ◌ັຍະ
ວ	ັວ␣ົວະ␣ົວ␣ວາ␣␣ິວ␣ີວ␣ຽວ␣ແ◌ວ␣າວ

Show details about glyph positioning

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.

• 5 pre-base, eg. ໂກ ōk̯ (ko)
• 3 post-base, eg. ກາ k̯ā
• 7 superscript, eg. ກິ k̯i
• 2 subscript, eg. ກຸ k̯u
• 1+6 sup+post-base, eg. ກັຍ k̯äɲ̱ kaj
• +3 post+post-base, eg. ກາຍ k̯āɲ̱ kaːj
• +5 pre+post-base, eg. ເກະ ēk̯a ke
• +4 pre+superscript, eg. ເກິ ēk̯i kɤ
• +1 super+post+post, eg. ກົວະ k̯ow̱a kuə
• +1 pre+post+post, eg. ເກາະ ēk̯āa kɔ
• +4 pre+sup+post-base, eg. ເກົາ ēk̯oā kaw
• +2 pre+sup+post+post-base, eg. ເກັຍະ ēk̯äɲ̱a kia

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

Lao uses a silent ອ as a base (although it is often transcribed as ʔ), to which vowel signs are applied, eg.

ໂອ

ອຸ່ນ

ຊາວເອັດ

Lao has no independent vowel letters, but when 0EAD is used as a vowel in a closed syllable it indicates the vowel ɔː.

ຈອກ

Tones

The Unicode Lao block provides the following characters for indicating tone.

The tone is expressed using 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 marks should be typed and stored in memory 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 ຳ, even though it will be displayed above the nikhahit.

ນ້ຳ

The following chart shows how to tell which tones are associated with a syllable. 'Checked' means ending in the sound -p, -t, or -k or a short vowel.

Vowel sounds to characters

Consonant summary table

The following table summarises the main consonant to character assigments.

The initial consonants are split across high, mid, and low columns.

For additional details see consonant_mappings.

Consonant letters

Each of the basic consonants is associated with one of 3 classes (high, mid, and low), that play a part in indicating the tone of the syllable (see tones). In only a few cases, though, does this lead to more than one letter for a given consonant.

The pronunciation of a letter often differs when the consonant is the onset or coda of a syllable.

The panel below lists the basic consonant letters for Lao, with typical pronunciations for syllable onset and final positions.

In the following lists, the class of each consonant is shown just below the IPA data. If a dash appears after the IPA transcription, it indicates the pronunciation in syllable-initial position; before indicates the pronunciation for syllable codas.

high

mid

low

High class nasals & liquids with HO

Gaps in the high class range can be filled by using a silent ຫ before the onset characters listed just below to make their default tonal class high. Note that this doesn't set a high tone, it just changes the class of the consonant, to which tone rules are then applied.

ຫມ␣ຫນ␣ຫຍ␣ຫງ␣ຫວ␣ຫລ␣ຫຽ

show composition

ຫວ່າງ

In modern texts, 3 of these combinations are typically represented by one of the following alternate forms.

ໝ␣ໜ␣ຫຼ

Two combinations can be represented as ligatures, for which there are separate characters in Unicode: 0EDD and 0EDCd,462, eg.

ໝາ

ໜອນ

A third can be represented by 0EAB 0EBCu,378, eg.

ຫຼາຍ

Wiktionary lists most of the 2-letter spellings as dated when the following 3 alternatives could be used, instead.

Onsets

Modern Lao really only has one audible, syllable-initial cluster, and that occurs when ວ labialises one of just over half a dozen initial consonants (see structure). In those cases, the initial consonant is simply followed by ວ. Note that the tone mark goes over the second character in the digraph in the following example.

ກວ້າງ

Lao does, however, have clusters of written consonants at the syllable onset where ຫ is used to change the class of a following consonant. This includes the use of Lao's one subjoined consonant mark in the combination ຫຼ. This is described in highclass.

ຫຍ້າ

Finals

With one exception, Lao doesn't have any special code points dedicated solely to syllable final consonants, although consonants do appear in those positions, eg. ນົກ

This is true whether or not the syllable coda is followed by another syllable.

However, only the following consonants appear in syllable-final position. Note how the sound may change, compared to when the same letter is used in syllable-initial position: where there is more than one phonetic realisation, the one with a preceding hyphen is the final.

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

The exception is that the rhyme -am may sometimes be represented by 0EB3.

ນຳ

Consonant clusters

See onsets for the few consonant clusters that occur at the beginning of a syllable.

Otherwise, consonant letter clusters only occur where a syllable ends with a consonant and another syllable begins.

Because the orthography is alphabetic, rather than an abugida, vowel absence after syllable-final consonants does not normally need to be marked in any way. The absence of a vowel sound is simply indicated by the absence of a vowel sign. The following example has 2 instances of a syllable-final consonant followed by an onset, one word-internal, and the other between words.

ອັກສອນລາວ

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

0EBA is used as a virama when writing Pali. It is not used in modern Lao.

0ECC was previously used to indicate silenced consonants, but is now described as obsolete.wl,#Punctuation

Onsets

Finals

Pali characters

VOWEL SIGN EI

In complex scripts, visually similar or identical glyph patterns can often be made from a sequence of code points rather than the single code point that Unicode provides. These are not made the same by normalisation, and they are not semantically equivalent. These inappropriate sequences should be avoided because they will cause the meaning of the text to change; searches, matching and other aspects of the text will fail to be understood by the application or the font.

Only one such is listed in the table below, The single code point on the left should be used, and not the sequence on the right. In some cases, fonts will indicate that there is a problem by forcing the appearance of a dotted circle or otherwise failing to render the text correctly, but this may not always be the case.

VOWEL SIGN AM

The combination of nikahit and sara aa is normally written with the precomposed character in the Lao block. It is possible to use 2 code points to create something that may visually look identical (and is in fact used during justification), but the single character and the sequence are not converted to each other during normalisation; therefore, the text will be read as different by normalisation-based matching algorithms.

Code point sequences

Tone marks should be typed and stored after any combining vowel mark. Fonts will typically indicate visually that the order is incorrect because the tone mark will appear below the vowel mark if they are the wrong way around.

Lao is visually encoded so pre-base glyphs are associated with ordinary spacing characters, and these need to be typed and stored in visual order relative to the base consonant(s) in a syllable. If the syllable begins with a consonant cluster such as pr, the pre-base code points must be typed before the p, even though they are pronounced after the r.

Digits

Lao uses Western digits.

There is, however, a set of Lao digits.

Observation: Pending further clarification about how widespread the use of Lao digits is, note that Lao Wikipedia uses Lao digits for table of contents list numbering and for footnote references. See the relevant sections below.

The CLDR standard-decimal pattern is #,##0.###. The standard-percent pattern is #,##0%.cldr

Observation: Lao Wikipedia uses a French pattern, #.##0,###, eg. ມີກຳລັງຕິດຕັ້ງ 7.207,24 ເມກາວັດ There are 7,207.24 megawatts installed

Currency

The CLDR standard format for currency is ¤#,##0.00;¤-#,##0.00, and the symbol for the Lao currency, Kip, is ₭.cldr

Context-based shaping & positioning

Pre-base vowels are visually ordered, and therefore do not need to be repositioned by the font.

Vowel signs, tones, and one consonant, on the other hand, are combining characters that need to be correctly positioned relative to the base character, and multiple marks can be combined with a single base character.

When using the vowel sign AM with a tone mark the small circle needs to push the tone mark upwards, even though the tone mark occurs before the vowel sign in memory (see fig_tone_am).

Letterform slopes, weights, & italics

Observation: Italicised text used for a figure captions, and also for quotations.

Word boundaries

Words are not separated by spaces, nontheless double-clicking or other selection methods are expected to identify word boundaries. There are 2 alternative approaches for managing this.

1. An application uses a dictionary or smart algorithm to parse the text and determine word boundaries.
2. The author uses 200B (ZWSP) between words when creating the content.

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-based segmentation must identify and keep together any syllable-initial clusters involving h or l, for example, the initial 2 letters in ຫມາ should wrap as a unit just like the ligated form, ໝາ mā.

What about kw etc?

While nearly all syllables can be argued to be words in their own right, there is still a preference for keeping multi-syllabic words together during word-based segmentation. eg. ປະເທດ For this, an application needs to use a dictionary to parse Lao text.

However, widely used software automatically inserts 200B in Lao text at word or syllable boundaries, and many web pages use such inserted ZWSP characters to get browsers to wrap correctly.g3,#issuecomment-385847864

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

If dictionaries are used for segmentation, they should be selected based on the language, not the script. (See the list of languages using the Lao script.)

Graphemes

Phrase & section boundaries

Lao uses ASCII punctuation, but also uses space as punctuation.

Spaces are used, but represent phrase or sentence boundaries.

Numbers are also normally surrounded by spaces.

In principle, periods are not used, though this appears to be changing.wl,#Punctuation

Observation: Lao Wikipedia uses periods at the end of sentences, and commas (see an example).l An online news site also consistently uses periods to end sentences.

Western punctuation is also used. Contemporary writing may include punctuation marks borrowed from French, such as the exclamation mark (!), and question mark (?). However, questions can be determined by question words within a sentence.wl,#Punctuation

Hyphens are also commonly found in modern writing.wl,#Punctuation

Quotations & citations

Lao texts use quotation marks around quotations. Of course, due to keyboard design, quotations may also be surrounded by ASCII double and single quote marks.

The default quote marks for Lao are “ at the start, and ” at the end.cldr

When an additional quote is embedded within the first, the quote marks are ‘ and ’.cldr

Contemporary writing may also include « and » for quotation marks, borrowed from French.wl,#Punctuation

Abbreviation, ellipsis & repetition

Other inline features

Line-breaking & hyphenation

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

See word for a discussion of issues related to word-based segmentation.

Text alignment & justification

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

Baselines, line height, etc.

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

Lao places vowel and tone marks above base characters, one above the other, and can also add combining characters below the line. The complexity of these marks means that the vertical resolution needed for clearly readable Lao text is higher than for English, or most Latin text. In addition, Lao also tends to add more interline spacing than Latin text does.

To give an approximate idea, fig_baselines compares Latin and Lao glyphs from Noto fonts. The basic height of Lao letters is typically slightly above the Latin x-height, however extenders and combining marks reach well beyond the Latin ascenders and descenders, creating a need for larger line spacing.

fig_baselines_other shows similar comparisons for the Lao MN and DokChampa fonts.

Counters, lists, etc.

You can experiment with counter styles using the Counter styles converter. Patterns for using these styles in CSS can be found in Ready-made Counter Styles, and we use the names of those patterns here to refer to the various styles.

The modern Lao orthography uses a numeric style.

Prefixes and suffixes

Observation: Lao Wikipedia uses periods for suffixes.l

Styling initials

It is possible to find the first letter in a paragraph styled so that it is larger and sits alongside several lines of the continuing paragraph text.

Observation: All combining characters, including spacing ones, are included in the selections shown in fig_drop_caps.

Any punctuation such as opening quotes and opening parentheses should also be included in the initial styling. ?

Observation: In the figures shown, the alphabetic baseline of the highlighted letter(s) matches the bottom of the row that determines the size of the highlighted letter(s). Selections without diacritics above are somewhat shorter than the height of the lines alongside, whereas selections with multiple diacritics rise slightly higher than the first line of text.

Observation: In fig_drop_caps_2, the selection picks out only ຫ from the digraph ຫລ; and ເ from the syllable ເມຶ່ອ.

Notes, footnotes, etc

Observation: Lao Wikipedia uses Lao digits for footnote references.