Braille

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The Braille system is a method that the blind use to read and write. Each Braille character or "cell" is made up of six dot positions, arranged in a rectangle comprising of two columns of three dots each. A dot may be raised at any of the six positions to form many combinations. Counting the space, in which no dots are raised, there are sixty four such combinations. For reference purposes, a particular combination may be described by naming the positions where dots are raised, the positions being universally numbered 1 through 3 from top to bottom on the left, and 4 through 6 from top to bottom on the right. For example, dots 1-3-4 would describe a cell with three dots raised, at the top and bottom in the left column and on top of the right column.

Contents

The Braille alphabet

Braille generally consists of cells of 6 raised dots arranged in a grid of two dots horizontally by three dots vertically. The dots are conventionally numbered 1, 2, 3 from the top of the leftward column and 4, 5, 6 from the top of the rightward column.

Image:Brajlo.gif

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.

As originally conceived by Louis Braille, a sequence of characters, using the top 4 dots of the braille cell, represents letters "a" through "j". Dot 3 is added to each of the "a" through "j" symbols to give letters "k" through "t". Both of the bottom dots (dots 3 and 6) are added to the symbols for "a" through "e" to give letters "u", "v", "x", "y", and "z". The letter "w" is an exception to the pattern because French did not make use of the letter "w" at the time Louis Braille devised his alphabet, and thus he had no need to encode the letter "w".

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. In practice, Braille produced in the United Kingdom does not have capital letters.

There are braille codes for representing shorthand (produced on a machine which embosses a paper tape) and for representing mathematics (Nemeth Braille) and musical notation (Braille music).

Braille has been extended to an 8 dot code, particularly for use with braille embossers and refreshable braille displays. In 8 dot braille the additional dots are added at the bottom of the cell, giving a matrix 4 dots high by 2 dots wide. The additional dots are given the numbers 7 (for the lower-left dot) and 8 (for the lower-right dot). 8-dot braille has the advantages that the case of an individual letter is directly coded in the cell containing the letter and that all the printable ASCII characters can be represented in a single cell. 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.

Letters and numbers

A, 1

B, 2

C, 3

D, 4

E, 5

F, 6

G, 7

H, 8

I, 9

J, 0

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Other symbols

Capital letter follows

Number follows

Full stop/period

Comma

Question mark

Semicolon

Exclamation point

Opening quotation mark

Closing quotation mark

Bracket

Hyphen

Unicode rendering table

Braille Letter Braille Letter
⠁ A 1 ⠞ T
⠃ B 2 ⠥ U
⠉ C 3 ⠧ V
⠙ D 4 ⠺ W
⠑ E 5 ⠭ X
⠋ F 6 ⠽ Y
⠛ G 7 ⠵ Z
⠓ H 8 ⠠ Capital sign
⠊ I 9 ⠼ Number sign
⠚ J 0 ⠲ Period
⠅ K ⠂ Comma
⠇ L ⠦ Question mark
⠍ M ⠆ Semicolon
⠝ N ⠖ Exclamation mark
⠕ O ⠦ Opening quote
⠏ P ⠴ Closing quote
⠟ Q ⠶ Bracket
⠗ R ⠤ Hyphen
⠎ S    

Braille transcription

Image:Braille Writer.jpg 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 visually impaired people; 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.

Though Braille is thought to be the main way blind people read and write, in Britain (for example) out of the reported 2 million visually impaired population, it is estimated that only around 15-20 thousand people use Braille. Younger people are turning to electronic text on computers instead; a more portable communication method that they can also use with their friends. A debate has started on how to make Braille more attractive and for more teachers to be available to teach it.

Braille for other scripts

There are many extensions of Braille for additional letters with diacritics, such as ç, ô, é.

When Braille is adapted to languages which do not use the Latin alphabet, the blocks are generally assigned to the new alphabet according to how it is transliterated into the Latin alphabet, and the alphabetic order of the national script (and therefore the natural order of Latin Braille) is disregarded. Such is the case with Russian, Greek, Hebrew, Arabic, and Chinese. In Greek, for example, gamma is written as Latin g, despite the fact that it has the alphabetic position of c; Hebrew beth, the second letter of the alphabet and cognate with the Latin letter b, is instead written v, as it is commonly pronounced; Russian ts is written as c, which is the usual letter for /ts/ in the Slavic languages which use the Latin alphabet; and Arabic f is written as f, despite being historically p, and occurring in that part of the Arabic alphabet (between historic o and q). In Chinese Braille, which is based on Zhuyin rather than the Latin Pinyin alphabet, there are additional blocks for the tones, diphthongs, and vowel + final consonant combinations, as well as Latin Braille blocks for the initial consonants and simple vowels. There are separate systems based on different spoken variants of Chinese.

However, at least two adaptations of Braille have completely reassigned the Latin sound values of the blocks. These are:

In Japanese Braille, the alphabetic signs for a consonant and vowel are combined into a single syllabic block; in Korean Braille, the consonants have different syllable-initial and syllable-final forms. These modifications made Braille much more compatible with Japanese kana and Korean hangul, but meant that the Latin sound values could not be maintained.

See also

External links

Retrieved from "http://en.freepedia.org/Braille.html"


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