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 can be made 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 special braille typewriter or "Perkins Brailler", or produced by a braille embosser attached to a computer. It may also be made using a refreshable braille display.
The six bit braille code is very limited, it only allows 64 different possible combinations. This means that many things need more than one braille character to be coded. One example for this is how numbers are coded in English braille: First there is a symbol that says the next symbol is a number, and then there is the symbol for the number. The symbol for "number" is usually given only once; every symbol that follows is treated as a number, until there is a space.
Braille has been extended to an 8 dot code, particularly for use with braille embossers and refreshable braille displays. In 8 dot braille the added dots are added at the bottom of the cell, giving a cell 4 dots high by 2 dots wide. The additional dots are called 7 (for the lower-left dot) and 8 (for the lower-right dot). 8-dot braille has the advantages that capital and lower cases of the letters are directly coded in the cell, a capital letter does not need two cells. All the printable ASCII characters can be represented in a single cell, and all 256 possible combinations of 8 bits are encoded by the Unicode standard. Braille with six dots is frequently stored as braille ASCII.
It is possible to transcribe braille by replacing each letter with the braille code for the letter. This is usually known as "Grade 1 Braille". Grade 1 braille is mostly used by beginners.
The basic problem of Grade 1 braille is that braille "letters" are much larger than printed ones. The standard page is 11"x11" (28 cm by 28 cm) in size and only has room for twenty-five lines of forty characters. This means a book would need to be very thick compared to a standard printed book.
For this reason almost all English braille books use a transcription known as "Grade 2 braille". Grade 2 braille uses contractions, which allows to save space and increase reading speed. Grade 2 braille was developed by linguists (people who study languages), who also looked at customs, styles and practices. Transcribing a text into Grade 2 braille is difficult, and the people doing the transcription need to have a special education.
In English, there are 23 words which are replaced with a single letter. That way, the word "but" is contracted (shortened) to the single letter "b," "can" to "c", "do" to "d", and so on. Even this simple rule has exceptions and special cases, which must be thought of. As an example, only the verb "to do" is replaced by "d", the noun "do" (which stands for a note in music) is a different word, and is written in full.
Sometimes, part of words are contracted, and a character can mean different things in different parts of a word. There are many rules for 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 cannot be used when it would make a problem with a prefix or suffix on the word. Also, some rules are flexible and may depend on the situation. So when the rules permit the same word to be written in more than one way, preference is given to "the contraction that is closer to the correct pronunciation."
"Grade 3 Braille" is a system that includes many additional contractions. It is almost like a shorthand. It is rarely used for books, but people use it to be able to write and read fast, for themselves. It can be used for taking notes.
Only very few people can use grade 4 braille. It uses many rules to shorten grade 3 even further. It allows a blind person to use shorthand to follow spoken conversation. Very often, systems of seven or eight dots are used.
The current Canadian paper money has raised dots on the bills that shows its value. This helps blind people who might otherwise be cheated. This 'tactile feature' does not use standard braille but, instead, a system developed by working with blind and visually impaired Canadians after they found that not all people who needed it could read braille.
Braille may not be the main way blind people read and write. In Britain (for example), of the two million visually impaired people, "only about 15-20 thousand use Braille". In the U.S.A. according to the 2015 "Annual Report" from the American Printing House for the Blind, there were 61,739 legally blind students registered in the U.S. Of these, only "8.6% (5,333) were registered as braille readers", 31% (19,109) as visual readers, 9.4% (5,795) as auditory readers, 17% (10,470) as pre-readers, and 34% (21,032) as non-readers.
Currently, among the estimated 85,000 blind adults in the United States, 90% of those who are Braille-literate are employed. Among adults who do not know Braille, only 33% are employed.
Younger people are turning to electronic text on computers which can be read aloud by software programs. This is a good communication method they can use with their friends. Inevitably, software will go on advancing, as it does in all its functions. Also, there are audio sources for literature: some are available for use without computer links. Much thought is going into all these issues.
A term which is useful to know is "accessible publishing": Accessible publishing means books and other texts are available in formats designed to aid or replace the reading process. Examples are: varieties of larger fonts, specialised fonts for certain kinds of reading disabilities, Braille, e-books, and automated Audiobooks and digital talking books. This means that Braille is only one way for sighting-impaired people to go; also that there are many more partially sighted people than registered blind people. The partially sighted obviously have more choices.
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, not the alphabetic order of the national script. This is the case with Russian (Cyrillic alphabet), Greek, Hebrew, Arabic, and Chinese. In Greek, for example, "gamma" is written as Latin "g", even though it is the third letter of that alphabet (like the Latin "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. Esperanto letters with circumflexes, "ĉ", "ĝ", "ĥ", "ĵ" and "ŝ", are written as those letters without circumflexes with a filled sixth dot.
More differences are in Chinese braille. In Mandarin Braille, which is based on Zhuyin rather than the Latin Pinyin alphabet, the Latin braille values are used for the first consonants and the simple vowels. There are additional blocks for the tones, diphthongs, and any following vowel + consonant combinations. Cantonese Braille is also based on Latin braille for many of the initial consonants and simple vowels, but the blocks also have different values depending on whether they are in a leading syllable or following syllable position. For instance, the block for Latin "k" represents old-style Cantonese "k" ("g" in Yale and other modern Romanizations) when initial, but "aak" when final, while Latin "j" represents Cantonese initial "j" but final "oei".