Braille is a tactile writing system used by blind people. It was invented by Louis Braille of France who was blinded in a childhood accident. At the age of 15 he modified a military system for reading orders at night without showing any light (night writing), inventing Braille. Braille originally lacked an encoding for the letter W.
Braille is also notable for being a binary code that predated the invention of the computer.
The Braille alphabet
Braille generally consists of cells of 6 raised dots conventionally numbered
and the presence or absence of dots gives the coding for the symbol. Dot height is approximately 0.02 inches (0.5 mm); the horizontal and vertical spacing between dot centers within a braille cell is approximately 0.1 inches (2.5 mm); the blank space between dots on adjacent cells is approximately 0.15 inches (3.75 mm) horizontally and 0.2 inches (5.0 mm) vertically. A standard braille page is 11 inches by 11 inches and typically has a maximum of 40 to 42 braille cells per line and 25 lines on a page.
English braille codes the letters and punctuation, and some double letter signs and word signs directly, but capitalisation and numbers are dealt with by using a prefix symbol.
Braille has been extended to an 8 dot code so that the case of an individual letter is directly coded in that cell, and so that all the printable ASCII characters can be represented. All 256 possible combinations of 8 dots are encoded by the Unicode standard.
Braille may be produced using a "slate" and a "stylus" in which each dot is created from the back of the page, writing in mirror image, by hand, or it may be produced on a braille typewriter or "Perkins Brailler", or produced by a Braille Embosser attached to a computer. It may also be rendered using a refreshable Braille display.
A1 B2 C3 D4 E5 F6 G7 H8 I9 J0 X. X. XX XX X. XX XX X. .X .X .. X. .. .X .X X. XX XX X. XX .. .. .. .. .. .. .. .. .. ..
K L M N O P Q R S T X. X. XX XX X. XX XX X. .X .X .. X. .. .X .X X. XX XX X. XX X. X. X. X. X. X. X. X. X. X.
U V W X Y Z X. X. .X XX XX X. .. X. XX .. .X .X XX XX .X XX XX XX
Capital Number Question sign sign Period Comma mark .. .X .. .. .. .. .X XX X. X. .X XX .X .. XX
Exclam. Opening Closing Semicolon point quote quote Bracket Hyphen .. .. .. .. .. .. X. XX X. .X XX .. X. X. XX XX XX XX
Next time you're in an elevator, check the braille:
.X XX .X X. XX ..
... means this is the button for the sixth floor (number sign + F).
The Braille alphabet in Unicode characters:
|(||H 8||(||Capital sign|
|(||I 9||(<||Number sign|
Although it is possible to transcribe Braille by simply substituting the equivalent Braille character for its printed equivalent, such a character-by-character transcription, known as Grade 1 Braille, is used only by beginners.
Braille characters are much larger than their printed equivalents, and the standard 11" by 11" (28 cm × 28 cm) page has room for only 25 lines of 40 characters. To reduce space and increase reading speed, virtually all Braille books are transcribed in what is known as Grade 2 Braille, which uses a system of contractions to reduce space and speed the process of reading. As with most human linguistic activities, Grade 2 Braille embodies a complex system of customs, styles, and practices. The Library of Congress's Instruction Manual for Braille Transcribing runs to nearly 200 pages. Braille transcription is skilled work and Braille transcribers need to pass certification tests.
The system of Grade 2 Braille contractions begins with a set of 23 words which are contracted to single characters. Thus the word but is contracted to the single letter b, can to c, do to d, and so on. Even this simple rule creates issues requiring special cases; for example, d is, specifically, an abbreviation of the verb do; the noun do representing the note of the musical scale is a different word, and must be spelled out.
Portions of words may be contracted, and many rules govern this process. For example, the character with dots 2-3-5 (the letter "f" lowered in the braille cell) stands for "ff" when used in the middle of a word. At the beginning of a word, this same character stands for the word "to" although the character is written in braille with no space following it. At the end of a word, the same character represents an exclamation point.
The contraction rules take into account the linguistic structure of the word; thus, contractions are not to be used when their use would alter the usual braille form of a base word to which a prefix or suffix has been added. And some portions of the transcription rules are not fully codified and rely on the judgement of the transcriber. Thus, when the contraction rules permit the same word in more than one way, preference is given to "the contraction that more nearly approximates correct pronunciation."
Grade 3 Braille is a system that includes many additional contractions, almost a shorthand; it is not used for publication, but is used mostly for individuals for their personal convenience.
The current series of Canadian banknotes have raised dots on the banknotes that indicate the denomination and can be easily identified by the visually impaired; this 'tactile feature' does not use standard Braille but, instead, a system developed in consultation with blind and visually impaired Canadians after research indicated that not all potential users read Braille.
- Braille Course of University of São Paulo (http://www.braillevirtual.fe.usp.br)
- Unicode reference glyphs for Braille patterns (http://www.unicode.org/charts/PDF/U2800.pdf)
- Robert B. Irwin's As I Saw It (http://www.nyise.org/blind/irwin2.htm), 1955, gives a history of the "War of the Dots" that ultimately led to the adoption of the English form of the braille literary code in the United States and the demise of American braille and New York Point, its main competitors.
- The National Library for the Blind (http://www.nlb-online.org)
- Unified (English) Braille Code (http://www.iceb.org/ubc.html) (including information specific to British Braille)
- English Braille: American Edition (http://www.brl.org/ebae/)