Thai and Lao Braille
Thai Braille (อักษรเบรลล์) is the braille alphabet of the Thai language. It was adapted by Genevieve Caulfield, who knew both English and Japanese Braille. Unlike the print Thai alphabet, which is an abugida, Thai Braille has full letters rather than diacritics for vowels. However, traces of the Thai abugida remain: Only the consonants are based on the international English/French standard, while the vowels are reassigned and the five vowels transcribed a e i o u are taken from Japanese Braille.
With a few minor modifications, it's also used for Lao.
Consonants follow English and international conventions except where, as in b and f, there is interference from the Japanese-derived vowels. Low-tone-class kh, ng, ch, s, th, f are derived from English Braille k, g, st, s, th, f by adding dot 6. B and low ph are derived from high ph through reflection; p is a superposition of b and ph; the three consonants had been transcribed b, bp, p in Caulfield's day.
|ฎ d||ฏ t||ฐ th||ฑ th||ฒ th||ณ n|
Letters with asterisks are obsolete. Light cells are high tone-class letters in Thai, medium cells mid tone class, and dark cells low tone class. Consonants of different tone classes have distinct braille letters; complete homonyms (found in Thai only) are distinguished by prefixes. The one prefix in Lao is found with what was historically y, but is written as in the Thai y that was historically ny.
In Lao, ⠓ h is prefixed to ⠻⠽⠝⠍⠇⠺ ng ny n m l w to make move them to the high-tone class.
The short vowels transcribed a e i o u are taken from Japanese Braille, and the long vowels ā ē ī ō ū are derived from these. ⠕ ǫ (ɔ) is French/international o, and ⠪ eu/ue is French œ. The other vowels have little recognizable connection to other braille alphabets.
All vowels are written after the consonant in braille, regardless of their order in print. Although the vowels have different forms in print, depending on their environment, they have a single form in braille with few exceptions (short a and in Lao short o).
*Lao has reassigned ⠉ to ◌ົ o and moved ◌ຸ u to ⠤.
When 〈ะ〉 is used in print to indicate a short vowel, 〈⠁〉 is appended to the vowel in braille. Similarly, ฤา and ฦา are written as ฤ or ฦ plus า in braille as they are in print. The one irregularity in Thai, also found in Lao, is 〈⠕⠁〉 for 〈เ–าะ〉 short ǫ, written in braille though not in print as the short variant of ⠕ –อ long ǭ. Lao has additional, similar regularization of print conventions: ⠩⠁ for short ເ◌ິ oe, and similarly the braille short sign for a different print diacritic in short ເ◌ຶອ eua and ເ◌ັຍ ia.
The short sign, ⠄ ็, is also used for the rarer virama ฺ .
Numbers are the same as in other braille alphabets, though dot six ⠠ is prefixed to the ⠼ to specify that they're Thai/Lao digits.
Single (though not paired) clause-final punctuation may introduced with ⠸, but is otherwise as in English Braille.
There is some variability in the use of the ⠸ to mark stop/period, comma, and the exclamation point. Thai Braille seems to use ⠄ for the comma, while Lao Braille uses ⠸⠂, unless the latter is a copy error in Unesco (2013).
|“ ”||( )||........||-----|
- คู่มือการอ่าน การเขียน และการผลิตเอกสารอักษรเบรลล์ขั้นพื้นฐาน
- UNESCO (2013) World Braille Usage, 3rd edition.