Thai and Lao Braille

Braille charts

Thai and Lao Braille run as follows:

Consonants

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.

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 in (ຢ ⠠⠽ y), which corresponds to Thai ying (ญ ⠠⠽ y) in Braille but corresponds to Thai yak (ย ⠽ y) in alphabetic (non-Braille) position. Lao (ຍ ⠽ ny) corresponds to Thai yak (ย ⠽ y) in Braille and looks but corresponds to Thai ying (ญ ⠠⠽ y) in alphabetic position.

In Thai, ⠓ h is prefixed to low-class nasal stops and non-plosives ⠻⠀⠠⠽⠀⠝⠀⠍⠀⠗⠀⠇⠀⠺ ng y n m r l w to move them to the high-tone class. Lao has the same system for similar characters ⠻⠀⠽⠀⠝⠀⠍⠀⠇⠀⠺ ng ny n m l w.

Vowels

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. ⠕ aw () is French and international o, and ⠪ eu/ue is French œ. The other vowels have little recognizable connection to other braille alphabets.

All vowels, including the default, 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). ⠕ is both the inherent vowel aw and the null consonant, so the syllable aw is written ⠕⠕.

*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. ฤๅ and ฦๅ are written as ฤ or ฦ plus า in braille. 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.

Tone letters

Other symbols

The short sign (⠄ ็) is also used for the rarer virama (⠄ ฺ).