Braille and its principles

Braille is a tactile writing system, created by French blind educator Louis Braille (1806—1852).

Printed braille is based on a combination of 1 to 6 raised dots within a single cell arranged in a 3 × 2 dot matrix (three dots in two columns, and are uniquely numbered here (see picture on the right).

Thus, there are a total of 64 possible combinations (including a space character and a 6-dot braille cell with all six dots raised).

image (six-dot braille cell)

Braille dots in braille cell

Braille table

The Braille characters can be arranged in a table (see picture on the right) which shows, among other things, how systematically the combinations were designed.

The order of the combinations has undergone partial changes since their inception, but now most modern national standards use the first 25 characters (the basic characters of the Latin alphabet) with the same base value. The other characters are then used for both the accented characters of a particular alphabet and the diphthongs, so their meaning varies from language to language (see examples below).

image (braille character 146 with its different interpretation)

Braille table — the first two and half rows are international, the others in this table are the Czech national standard

Punctuation and composition signs

Since braille has only 64 combinations in the six-dot variant, it does not cover all the combinations that are commonly used in visual alphabets. The number of possible combinations is thus increased by the use of composition signs (or prefixes), which modify the value of the character that follows (see examples).

For digital work with the use of braille displays, braille is based on a cell with eight dots, which further increases the number of possible combinations to 256.

Examples of composition signs (for capital letters and numbers)

Braille systems

Some languages have multiple braille-based systems — the difference between them is the accuracy with which they reflect the visual writing system of the language (let us say accuracy of its transcription).

For example, English officially has two systems:

  • Uncontracted (or Grade 1, in full spelling, consists of the letters of the alphabet, punctuation, numbers, and a few composition signs)

  • Contracted (or Grade 2, consists of Uncontracted Braille plus 189 contractions and short-form words).

For more details see e. g. English Braille.

Examples of Uncontracted and Contracted English Braille

German has up to three systems:

  • Basisschrift (no contractions is used for transcription; this system is very rarely used)

  • Vollschrift (uses eight simple contractions for common vowel and consonant groups)

  • Kurzschrift (contracted Braille — a system of abbreviations and shortening rules was created for it over time)

For more details see e. g. Das System der deutschen Blindenschrift.

Examples of Uncontracted and Contracted German Braille