Letter (alphabet)

A letter is a segmental symbol of a phonemic writing system. The inventory of all letters forms an alphabet. Letters broadly correspond to phonemes in the spoken form of the language, although there is rarely a consistent and exact correspondence between letters and phonemes. The word letter, borrowed from Old French letre, entered Middle English around 1200 AD, eventually displacing the Old English term bōcstæf (bookstaff). Letter is descended from the Latin littera, which may have descended from the Greek "διφθέρα" (, writing tablet), via Etruscan. A letter is a type of grapheme, which is a functional unit in a writing system: a letter (or group of letters) represents visually a phoneme (a unit of sound that can distinguish one word from another in a particular language). Letters are combined to form written words, just as phonemes are combined to form spoken words. A sequence of graphemes representing a phoneme is called a multigraph or polygraph. A digraph is a case of polygraphs consisting of two graphemes. Examples of digraphs in English include ch, sh, and th. Some phonemes are represented by three letters, called a trigraph, such as sch in German. The same letterform may be used in different alphabets but have different sounds. The letters , and look rather alike but are the Latin H, Greek eta and Cyrillic en respectively; conversely the letters , (sigma) and (Es (Cyrillic)) from these alphabets each represent (approximately) the same [s] sound. The basic Latin alphabet is used by hundreds of languages around the world, but there are many other alphabets.Specific names are associated with letters, which may differ with language, dialect, and history. Z, for example, is usually called zed in all English-speaking countries except the US, where it is named zee. As elements of alphabets, letters have prescribed orders, although this too may vary by language. In Spanish, for instance, is a separate letter, sorted separately from : this distinction is not usually recognised in English dictionaries.