Letter (alphabet)

Letters are graphemes that broadly correspond to phonemes, the smallest functional units of sound in speech.

A single phoneme may also be represented by multiple letters in sequence, collectively called a multigraph.

Conversely, the distinct forms of ⟨S⟩, the Greek sigma ⟨Σ⟩, and Cyrillic es ⟨С⟩ each represent analogous /s/ phonemes.

Letter ultimately descends from the Latin littera, which may have been derived from the Greek diphthera 'writing tablet' via Etruscan.

During the fifth and sixth centuries, the development of lowercase letters began to emerge in Roman writing.

[6] Finally, many slight letter additions and drops were made to the common alphabet used in the western world.

[7] A letter can have multiple variants, or allographs, related to variation in style of handwriting or printing.

Upper- and lowercase letters represent the same sound, but serve different functions in writing.

The terms uppercase and lowercase originated in the days of handset type for printing presses.

Ancient inscription on a vase featuring Greek letters
The American manual alphabet , an example of letters in fingerspelling
Transliterations and iconography of the Semitic script, the first consonantal alphabet
Ascenders (as in "h") and descenders (as in "p") make the height of lower-case letters vary.
Venn diagram of letters in the Greek , Cyrillic and Latin alphabets . Certain letters appear in two or more of these alphabets, although they may not represent the same sound.