Alphabet

An alphabet is a standard set of letters (basic written symbols or graphemes) which is used to write one or more languages based on the general principle that the letters represent phonemes (basic significant sounds) of the spoken language. This is in contrast to other types of writing systems, such as logographies, in which each character represents a word, morpheme or semantic unit, and syllabaries, in which each character represents a syllable.

A true alphabet has letters for the vowels of a language as well as the consonants. The first "true alphabet" in this sense is believed to be the Greek alphabet, which is a modified form of the Phoenician alphabet. In other types of alphabet either the vowels are not indicated at all, as was the case in the Phoenician alphabet (such systems are known as abjads), or else the vowels are shown by diacritics or modification of consonants, as in the devanagari used in India and Nepal (these systems are known as abugidas or alphasyllabaries).

There are dozens of alphabets in use today, the most common being the Latin alphabet (which was derived from the Greek). Many languages use modified forms of the Latin alphabet, with additional letters formed using diacritical marks. While most alphabets have letters composed of lines (linear writing), there are also exceptions such as the alphabets used in Braille, fingerspelling, and Morse code.

Alphabets are usually associated with a standard ordering of their letters. This makes them useful for purposes of collation, specifically by allowing words to be sorted in alphabetical order. It also means that their letters can be used as an alternative method of "numbering" ordered items, in such contexts as numbered lists.