A digraph or digram is a pair of characters used in the orthography of a language to write either a single phoneme, or a sequence of phonemes that does not correspond to the normal values of the two characters combined.
IJ is a digraph of the letters i and j. Occurring in the Dutch language, it is sometimes considered a ligature, or a letter in itself. In most fonts that have a separate character for ij, the two composing parts are not connected but are separate glyphs, which are sometimes slightly kerned.
Dutch orthography uses the Latin alphabet. The spelling system is issued by government decree and is compulsory for all government documentation and educational establishments.
French orthography encompasses the spelling and punctuation of the French language. It is based on a combination of phonemic and historical principles. The spelling of words is largely based on the pronunciation of Old French c. 1100–1200 CE, and has stayed more or less the same since then, despite enormous changes to the pronunciation of the language in the intervening years. Even in the late 17th century, with the publication of the first French dictionary by the Académie française, there were attempts to reform French orthography.
The diaeresis and the umlaut are two different diacritical marks that look alike. They both consist of two dots ¨ placed over a letter, usually a vowel; when that letter is an i or a j, the diacritic replaces the tittle: ï. In computer systems, both forms have the same code point. Their appearance in print or on screen may vary between typefaces but rarely within the same typeface.
The Latin script, also known as Roman script, is an alphabetic writing system based on the letters of the classical Latin alphabet, derived from a form of the Cumaean Greek version of the Greek alphabet used by the Etruscans. Several Latin-script alphabets exist, which differ in graphemes, collation and phonetic values from the classical Latin alphabet.
Vietnamese Braille is the braille alphabet used for the Vietnamese language. It is very close to French Braille, but with the addition of tone letters. Vietnamese Braille is known in Vietnamese as chữ nổi, literally "raised letters", while electronic braille displays are called màn hình chữ nổi.
Thai Braille (อักษรเบรลล์) and Lao Braille (ອັກສອນເບຣລລ໌) are the braille alphabets of the Thai language and Lao language. Thai Braille was adapted by Genevieve Caulfield, who knew both English and Japanese Braille. Unlike the print Thai alphabet, which is an abugida, Thai and Lao Braille have full letters rather than diacritics for vowels. However, traces of the abugida remain: Only the consonants are based on the international English and French standard, while the vowels are reassigned and the five vowels transcribed a e i o u are taken from Japanese Braille.
Russian Braille is the braille alphabet of the Russian language. With suitable extensions, it is used for languages of neighboring countries that are written in Cyrillic in print, such as Ukrainian and Mongolian. It is based on the Latin transliteration of Cyrillic, with additional letters assigned idiosyncratically. In Russian, it is known as Шрифт Брайля.
Greek Braille is the braille alphabet of the Greek language. It is based on international braille conventions, generally corresponding to Latin transliteration. In Greek, it is known as Κώδικας Μπράιγ Kôdikas Brég "Braille Code".
The Esperanto language has a dedicated braille alphabet. One Esperanto braille magazine, Esperanta Ligilo, has been published since 1904, and another, Aŭroro, since 1920.
The goal of braille uniformity is to unify the braille alphabets of the world as much as possible, so that literacy in one braille alphabet readily transfers to another. Unification was first achieved by a convention of the International Congress on Work for the Blind in 1878, where it was decided to replace the mutually incompatible national conventions of the time with the French values of the basic Latin alphabet, both for languages that use Latin-based alphabets and, through their Latin equivalents, for languages that use other scripts. However, the unification did not address letters beyond these 26, leaving French and German Braille partially incompatible and as braille spread to new languages with new needs, national conventions again became disparate. A second round of unification was undertaken under the auspices of UNESCO in 1951, setting the foundation for international braille usage today.
Armenian Braille is either of two braille alphabets used for writing the Armenian language. The assignments of the Armenian alphabet to braille patterns is largely consistent with unified international braille, with the same punctuation, except for the comma. However, Eastern and Western Armenian are assigned braille letters based on different criteria. The conventions for Western Armenian were developed in Lebanon.
French Braille is the original braille alphabet, and the basis of all others. The alphabetic order of French has become the basis of the international braille convention, used by most braille alphabets around the world. However, only the 25 basic letters of the French alphabet plus w have become internationalized; the additional letters are largely restricted to French Braille and the alphabets of some neighboring European countries.
Italian Braille is the braille alphabet of the Italian language, both in Italy and in Switzerland. It is very close to French Braille, with some differences in punctuation.
Portuguese Braille is the braille alphabet of the Portuguese language, both in Portugal and in Brazil. It is very close to French Braille, with slight modification of the accented letters and some differences in punctuation.
Turkish Braille is the braille alphabet of the Turkish language.
Several braille alphabets are used in Ghana. For English, Unified English Braille has been adopted. Four other languages have been written in braille: Akan (Twi), Ga, Ewe, and Dagaare. All three alphabets are based on the basic braille letter values of basic Latin alphabet:
Estonian Braille is the braille alphabet of the Estonian language.
Catalan Braille is the braille alphabet of the Catalan language. It is very close to French Braille: it uses the 26 letters of the basic braille alphabet, plus several additional letters for ç and what are, in print, vowel letters with diacritics; these differ from their French values only in the need to accommodate the Catalan acute accent: ú, ó, í for what are in French Braille ù, œ, ì :
