Six small dots, arranged like those representing the number six on a die, raised in different patterns: this is the basis for the Braille alphabet for the visually impaired, with each fingertip-readable pattern representing a letter, numeral, punctuation mark or symbol. It’s not a language but a code that can be used for many languages.

Louis Braille, born in 1809, was blinded by accident and infection as a small boy. Later, while attending the Royal Institute for Blind Youth in Paris, the 12-year-old was inspired by a code – devised by Charles Barbier, a retired captain in Napoléon Bonaparte’s army – that employed arrangements of 12 raised dots (to represent sounds rather than letters) and permitted silent battlefield communication at night.

The system was called sonography, or “night writing”, and though it proved too complex for its intended purpose, Braille mastered it, then adapted it, and finally presented his six-dot system based on the alphabet in 1824.

Codes for the world’s languages have been devised with reference to Louis Braille’s original assignments for the French alphabet. For non-Latin scripts, correspondences are based on orthographic or phonetic values, or historical connections. The Greek μ (mu) and the Arabic م (mim) use the code for “m”; the Greek γ (gamma) uses the code for “g” as it is romanised, not “c” as per its alphabetic order or its historical relation to the Latin letter c.

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Braille is used for ideographic systems, too: Hong Kong’s Cantonese Braille ( 點字 dím jih being “dot characters”, and 凸字 daht jih “raised characters”), mainland Chinese Braille for standard Mandarin, and Taiwanese Braille for Taiwanese Mandarin are phonetically based.

Each syllable is written with up to three Braille cells, representing initial consonant, rime (vowel and any final consonant) and tone (generally omitted for Mandarin systems), with punctuation, digits and Latin letters from the original Braille. Braille codes have also been developed for music (by Braille himself), mathematics, computer programming and chess.

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Two centuries on, technological advances support the world’s 250 million visually impaired people. Touchable ink that dilates with heat for an embossed effect, smartwatches that display scrolling messages four Braille characters at a time, Braille tablets for reading school materials, and other smart devices providing tactile graphics and images – all made affordable and accessible for developing countries.

January 4 was World Braille Day (and Louis Braille’s birth­day), commemorating the Frenchman’s huge contribution in providing a means of communication, as well as independence and equality, for the visually impaired.

Joyeux anniversaire, cher Louis!