Lao (draft)

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.

Observation. I'm not aware of any variant spellings or confusable characters.

Letters

Combining marks

Numbers

Punctuation

Symbols

Other

Vowel sounds

Consonant sounds

Initials

	labial	dental	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 values

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

Vowel signs

Although modern Lao orthography is alphabetic, and therefore has no inherent vowel, vowel signs are still used to write the vowel sounds. For example, ki is written:

ກິ ki [U+0E81 LAO LETTER KO + U+0EB4 LAO VOWEL SIGN I]

What's different is that ka, which would in an abugida be written just using a consonant, is also spelled out using a vowel sign.

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

Vowels in Lao are written with a mixture of combining characters and ordinary spacing characters. Only the superscript and subscript vowel signs are combining characters. It is also common to use some consonants to represent vowel sounds (see consonant_vowels).

Vowel signs are arranged around a syllable onset, which are rare in Lao but may include 2 consonants, rather than just around the immediately preceding consonant. For example, vowel characters that are rendered to the left of the base will appear before all the consonants in a syllable onset (see prebase_vowels). And where a vowel sign is composed of components that are rendered before and after the base, they will surround the syllable onset (see composite_vowels).

Combining marks used for vowels

Lao uses the following combining marks for vowels.

Letter characters used for vowels

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_vowels).

ຳ [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, but the Unicode Standard classifies it as a letter.

Pre-base vowel signs

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

details

ແມວ

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

ແກວ່ງ ໃຫຍ່ ເຫຼືອງ

Consonants used for vowel sounds

On its own, in the middle of a closed syllable, ອ [U+0EAD LAO LETTER O] is pronounced as the vowel -ɔː- and ວ [U+0EA7 LAO LETTER WO] is pronounced -uːə̯-, eg. ຈອກ tɕɔːk˧˩ glass ບວມ buːəm to swell

ອ [U+0EAD LAO LETTER O] is also used as a vowel carrier for standalone vowels (see standalone).

ວ [U+0EA7 LAO LETTER WO], ຍ [U+0E8D LAO LETTER NYO], and ຽ [U+0EBD LAO SEMIVOWEL SIGN NYO] also represent the glide w or j at the end of a diphthong (see composite_vowels).

ຽ [U+0EBD LAO SEMIVOWEL SIGN NYO] was originally an alternate form of non-initial ຍ [U+0E8D LAO LETTER NYO], but is now used for diphthongs, either alone as iːə̯ or as the semi-vowel j, eg. ປຽກ piːə̯k˧˩ wet ຊາຽ saːj˦ sand

All of these characters also appear in the composite vowels described below.

Composite vowels

In the lists below, hyphens represent consonants. Vowels used in closed syllables are indicated by a trailing hyphen in the IPA transcription.

Vowels in Lao are commonly written using a combination of code points, which may produce glyphs on more than one side of the base. See fig_composite.

details

ເຈັ້ຍ

Some composite vowels represent plain vowel sounds:

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

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

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

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:

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 ອ [U+0EAD LAO LETTER O] as a base (although it is often transcribed as ʔ), to which vowel signs are applied, eg. ໂອ ອຸ່ນ

Lao has no independent vowel letters.

Silent vowels & consonants

Because the orthography is alphabetic, vowel absence after syllable-final consonants is not normally marked in any way. Nor is it marked in syllable-initial clusters.

Vowel sounds to characters

This section maps Lao vowel sounds to common graphemes in the Lao orthography. The dash indicates the location of the consonant relative to the vowel sign; if there are 2 dashes, the vowel is used only in closed syllables. 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.

Tone marks

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

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 [U+0EB3 LAO VOWEL SIGN AM], and should be displayed above the nikhahit, see fig_tone_am.

Consonant letters

Consonant clusters

Phonetically, unlike Thai, Lao doesn't have syllable-initial consonant clusters other than those followed by w plus a non-rounded vowel (see structure). Those are written using an ordinary ວ [U+0EA7 LAO LETTER WO], eg. ຄວາຍ

Otherwise, consonant letter clusters occur in the following circumstances:

• Where a syllable begins with a silent ຫ [U+0EAB LAO LETTER HO SUNG] in order to change the tone (see highclass), eg. ຫຍັງ
• Where a syllable ends with a consonant and another syllable begins. The Lao for Lao script has several syllable-final consonants: ອັກສອນລາວ

No special characters or viramas are involved, except those described in highclass.

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

Final consonants

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

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

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

Consonant sounds to characters

This section maps Lao consonant sounds to common graphemes in the Lao orthography, grouped by high class ( h ), mid class ( m ), low class ( l ) and syllable-final ( f ).. 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.

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 ₭ [U+20AD KIP SIGN].cldr

Context-based shaping & positioning

Prescript vowels are visually ordered, and therefore do not need to be positioned 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).

Font styling & weight

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

Grapheme clusters

tbd

Unicode grapheme clusters divide text into segments that contain a single base consonant plus any following combining characters: the latter include the 9 combining vowel signs, and all tone marks. Not included are free-standing vowel signs and consonants that make up other parts of a composite vowel, both pre-base and post-base. Also, syllable-initial consonant clusters with -ວ [U+0EA7 LAO LETTER WO] and ຫ- [U+0EAB LAO LETTER HO SUNG] are treated as 2 text units, but not ຫຼ [U+0EAB LAO LETTER HO SUNG + U+0EBC LAO SEMIVOWEL SIGN LO].

This implies that a pre-base vowel sign such as ເ- [U+0EC0 LAO VOWEL SIGN E] would be treated as a separate item from what follows, and in fact this can be seen in fig_drop_caps_2, where that character is the only thing highlighted in an initial letter selection. (On the other hand, initial letters followed by combining characters select the whole sequence, as seen in fig_drop_caps.)

This means that Lao typography is different from some other SE Asian scripts where pre-base vowel signs are selected with the base because they are combining characters, or syllable-initial consonant clusters form a unit because the 'medial' consonants are represented by combining characters.

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 ​ U+200B ZERO WIDTH SPACE 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 ​ 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.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 ⁠ 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.

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.)

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

Bracketed text

Lao commonly uses ASCII parentheses to insert parenthetical information into text.

( [U+0028 LEFT PARENTHESIS] and ) [U+0029 RIGHT PARENTHESIS] are used for parentheses in contemporary 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 “ [U+201C LEFT DOUBLE QUOTATION MARK] at the start, and ” [U+201D RIGHT DOUBLE QUOTATION MARK] at the end.cldr

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].cldr

Contemporary writing may also include « [U+00AB LEFT-POINTING DOUBLE ANGLE QUOTATION MARK] and » [U+00BB RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK] for quotation marks, borrowed from French.wl,#Punctuation

Emphasis

tbd

Abbreviation, ellipsis & repetition

Inline notes & annotations

tbd

Other punctuation

CLDR includes the following punctuation.

Other inline text decoration

tbd

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.

Text spacing

tbd

This section looks at ways in which spacing is applied between characters over and above that which is introduced during justification.

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.