|Languages||Lao, Thai and others|
|The Brahmic script and its descendants|
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. It has 27 consonants (ພະຍັນຊະນະ [pʰāɲánsānā]), 7 consonantal ligatures (ພະຍັນຊະນະປະສົມ [pʰāɲánsānā pá sǒm]), 33 vowels (ສະຫລະ [sálā]), and 4 tone marks (ວັນນະຍຸດ [ván nā ɲūt]).
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.
Lao is traditionally written from left to right. Lao is considered an abugida, in which certain 'implied' vowels are unwritten. However, due to spelling reforms by the communist Lao People's Revolutionary Party, it is less apparent. Despite this, most Lao outside of Laos, and many inside Laos, continue to write according to former spelling standards, so vernacular Lao functions as a pure abugida. For example, the old spelling of ສເລີມ 'to hold a ceremony, celebrate' contrasts with the new ສະເຫລີມ. Vowels can be written above, below, in front of, or behind consonants, with some vowel combinations written before, over and after. Spaces for separating words and punctuation were traditionally not used, but a space is used and functions in place of a comma or period. The letters have no majuscule or minuscule (upper- and lowercase) differentiation.
The Lao script was slowly standardized in the Mekong River valley after the various Tai principalities of the region were merged under Lan Xang in the 14th century. This script, sometimes known as Tai Noi, has changed little since its inception and continued use in the Lao-speaking regions of modern-day Laos and Isan. Conversely, the Thai alphabet continued to evolve, but the scripts still share similarities. This[which?] script was derived locally from the Khmer script of Angkor with additional influence from Mon, both of which were ultimately derived from the Brahmic writing systems of India.
Traditionally, only secular literature were written with the Lao alphabet. Religious literature was often written in Tua Tham, a Mon-based script that is still used for the Tai Khün, Tai Lue, and formerly for Kham Mueang. Mystical, magical, and some religious literature was written in a modified version of the Khmer alphabet.
Essentially Thai and Lao are almost typographic variants of each other just as in the Javanese and Balinese scripts. The Lao and Thai alphabets share the same roots, but Lao has fewer characters and is written in a more curvilinear fashion than Thai. However this is less apparent today due to the communist party simplifying the spelling to be phonetic and omitting extra letters used to write words of Pali-Sanskrit origin.
There is speculation that the Lao and Thai script both derive from a common script due to the great similarities between the scripts. When examining older forms of Thai scripts, many letters are almost identical to the Lao alphabet and vice versa.
According to Article 89 of the 2003 Amended Constitution of the Lao People's Democratic Republic, the Lao alphabet, though originally used solely for transcribing the Lao language, is also used to write several minority languages. Some minority languages use separate writing systems; The Hmong have adopted the Roman Alphabet. An older version of the script was also used by the ethnic Lao of Thailand's Isan region before Isan was incorporated into Siam. Its use was banned[by whom?] and supplemented with the very similar Thai alphabet in 1871; however, the region remained culturally and politically distant until further government campaigns and integration into the Thai state (Thaification) were imposed in the 20th century.
The twenty-seven consonants of the Lao alphabet are divided into three tone classes—high (ສູງ [sǔːŋ]), middle (ກາງ [kaːŋ]), and low (ຕ່ຳ tām)—which determine the tonal pronunciation of the word in conjunction with the four tone marks and distinctions between short and long vowels. Aside from tone, there are twenty-one distinct consonant sounds that occur in the Lao language. Each letter has an acrophonical name that either begins with or features the letter prominently, and is used to teach the letter and serves to distinguish them from other, homophonous consonants. The letter ອ is a special null consonant used as a mandatory anchor for vowels, which cannot stand alone, and also to serve as a vowel in its own right.
The table below shows the Lao consonant, its name, its pronunciation according to the International Phonetic Alphabet (IPA), as well as various romanisation schemes, such as the French-based systems in use by both the US Board of Geographic Names and the British Permanent Committee on Geographical Names (BGN/PCGN), the English-based system in use by the US Library of Congress (LC), Royal Thai General System of Transcription (RTGS) used in Thailand, and finally its Unicode name. A slash indicates the pronunciation at the beginning juxtaposed with its pronunciation at the end of a syllable.
|Letter||Name||Initial position||Final position||Unicode||Tone Class|
|ກ||ກ ໄກ່||kāi, chicken||/k/||k||/k/||k||KO||Middle|
|ຂ||ຂ ໄຂ່||kʰāi, egg||/kʰ/||kh||/k/||k||KHO SUNG||High|
|ຄ||ຄ ຄວາຍ||kʷʰáːj, water buffalo||/kʰ/||kh||/k/||k||KHO TAM||Low|
|ງ||ງ ງົວ or ງູ||ŋúə, ox or ŋúː, snake||/ŋ/||ng||/ŋ/||ng||NGO||Low|
|ຈ||ຈ ຈອກ||tɕɔ̏ːk, glass||/tɕ/||ch||/t/||t||CO||Middle|
|ສ||ສ ເສືອ||sɯ̌ːə, tiger||/s/||s||/t/||t||SO SUNG||High|
|ຊ||ຊ ຊ້າງ||sâːŋ, elephant||/s/||x||s||/t/||t||SO TAM||Low|
|ຍ||ຍ ຍຸງ||ɲúŋ, mosquito||/ɲ/||gn||ny||y||–||–||NYO||Low|
|ດ||ດ ເດັກ||dék, child||/d/||d||/t/||t||DO||Middle|
|ຕ||ຕ ຕາ||tàː, eye||/t/||t||/t/||t||TO||Middle|
|ຖ||ຖ ຖົງ||tʰǒŋ, stocking||/tʰ/||th||/t/||t||THO SUNG||High|
|ທ||ທ ທຸງ||tʰúŋ, flag||/tʰ/||th||/t/||t||THO TAM||Low|
|ນ||ນ ນົກ||nōk, bird||/n/||n||/n/||ne||n||NO||Low|
|ບ||ບ ແບ້||bɛ̑ː, goat||/b/||b||/p/||p||BO||Middle|
|ປ||ປ ປາ||paː, fish||/p/||p||/p/||p||PO||Middle|
|ຜ||ຜ ເຜິ້ງ||pʰɤ̏ŋ, bee||/pʰ/||ph||–||–||PHO SUNG||High|
|ຝ||ຝ ຝົນ||fǒn, rain||/f/||f||/p/||p||FO TAM||High|
|ພ||ພ ພູ||pʰúː, mountain||/pʰ/||ph||/p/||p||PHO TAM||Low|
|ຟ||ຟ ໄຟ||fáj, fire||/f/||f||/p/||p||FO SUNG||Low|
|ມ||ມ ແມວ||mɛ́ːw, cat||/m/||m||/m/||m||MO||Low|
|ຢ||ຢ ຢາ||jaː, medicine||/j/||y||–||–||YO||Middle|
|ຣ||ຣ ຣົຖ or ຣະຄັງ||rōt, car or rākʰáŋ, bell||/r/,/l/||r||/n/||ne||n||LO LOOT||Low|
|ລ||ລ ລີງ||líːŋ, monkey||/l/||l||/n/||ne||n||LO LING||Low|
|ວ||ວ ວີ||víː, fan||/ʋ/,/w/||v||v,w||–||–||WO||Low|
|ຫ||ຫ ຫ່ານ||hāːn, goose||/h/||h||–||–||HO SUNG||High|
|ອ||ອ ໂອ||ʔòː, bowl||/ʔ/||–||–||–||O||Middle|
|ຮ||ຮ ເຮືອນ||hɯ́ːən, house||/h/||h||–||–||HO TAM||Low|
Note that the Unicode names for the characters ຝ (FO TAM) and ຟ (FO SUNG) are reversed. The same is true for ຣ (LO LING) and ລ (LO LOOT). This error was introduced into the Unicode standard and cannot be fixed, as character names are immutable.
Lao also uses digraphs based on combinations of silent ຫ ຫ່ານ with certain other consonants, some of which also have special ligature forms that are optionally used. Because the first silent component is of the 'high' tone class, all the digraphs and ligatures are also of the high tone class. The older versions of the script also included special forms for combinations of ພ (pʰ) + ຍ (ɲ), ສ (s) + ນ (n), and ມ (m) + ລ (l). In addition, consonant clusters that had the second component of ຣ (r) or ລ (l) were written with a special form ຼ underneath the consonant. Since these were not pronounced in Lao, they were removed during various spelling reforms, and this symbol only appears in the ligature ຫຼ.
|Letter||Initial position||Unicode||Tone Class|
|ໜ or ຫນ||/n/||n||n||High|
|ໝ or ຫມ||/m/||m||m||High|
|ຫຼ or ຫຣ||/r/,/l/||r||r||High|
|ຫຼ or ຫລ||/l/||l||l||High|
Lao characters in initial position (several letters appearing in the same box have identical pronunciation).
Lao characters in final position. In the old documents, the letter ຽ could be found in place of ຍ or ຢ.
ນ, ຣ, ລ
ບ, ປ, ພ, ຝ, ຟ
ຈ, ສ, ຊ, ດ, ຕ, ຖ, ທ
ກ, ຂ, ຄ
Vowels are constructed from only a handful of basic symbols, but they can be combined with other vowel forms and semi-vowels to represent the full repertoire of diphthongs and triphthongs used in the language. Vowels cannot stand alone or begin a syllable, so the null consonant, ອ, which can function as a vowel in its own right, is used as a base. The names of the vowels are just as easy as saying sala (ສະຫລະ, [sáʔlāʔ]) before the vowel sign. Some vowels have unique names, and these are ໃ- (ໄມ້ມ້ວນ, mâj muân, rolled stem), ໄ- (ໄມ້ມາຽ, mâj máːj, unwound stem), -ົ (ໄມ້ກົງ, . mâj kòŋ, straight stem), -ັ (ໄມ້ກັນ, . mâj kàn, ear stem), -ຽ (ວິຣາມ, vī ráːm), and -ໍ (ນິກຄະຫິດ, nīk kʰā hǐt). 
|Short vowels||Long vowels|
|◌ະ,- ັ◌||/a/||a||a||_າ||/aː /||a||ā||a||aa|
|ເ-າະ, -ັອ-||/ɔ/||o||ǫ||o||-ໍ, -ອ-||/ɔː/||o||ǭ||o|
|ເ-ັຍ, -ັຽ-||/iə/||ia||ເ-ຍ, -ຽ-||/iːə/||ia||īa||ia|
|-ົວະ, -ັວ-||/uə/||oua||ua||ua||-ົວ, -ວ-||/uːə/||oua||ūa||ua|
|ໄ-, ໃ-*, -ັຍ||/aj/||ai||ai or ay||-າຍ||/aːj/||ay||āi||ai|
|Hindu–Arabic numeral system|
|Positional systems by base|
|Non-standard positional numeral systems|
|List of numeral systems|
Note that the word "Sao" ("twenty" in English) is not a standard Thai word and is only used here to show the RTGS transcription of the Lao Xao (ຊາວ). The standard Thai word for twenty is instead Yi-Sip (ยี่สิบ).
In December 2011, the Lao Ministry of Science and Technology, in cooperation with the Ministry of Post and Telecommunications, officially authorized the use of Phetsarath OT as the standard national font.
The Phetsarath OT font was already adopted by the government in 2009; however, Lao users were unable to use it, as international software manufactures did not include the font in their software systems. Mobile devices were not able to use or show Lao language. Instead, mobile phone users had to rely on Thai or English as language.
The Laos Ministry of Post and Telecommunications asked local technicians to develop a software system of international standard that would enable the Phetsarath OT font to be like other font systems that local users could access.
The Unicode block for the Lao script is U+0E80–U+0EFF, added in Unicode version 1.0. The first ten characters of the row U+0EDx are the Lao numerals 0 through 9. Throughout the chart, grey (unassigned) code points are shown because the assigned Lao characters intentionally match the relative positions of the corresponding Thai characters. This has created the anomaly that the Lao letter ສ is not in alphabetical order, since it occupies the same code-point as the Thai letter ส.
Official Unicode Consortium code chart (PDF)