Semitic Šīn (bow) was pronounced as /S/ as the modern English digraph SH. In Greek, there was only one phoneme /s/ and no /S/, so Greek σιγμα (sigma) came to represent the Greek /s/ phoneme. The name "sigma" probably comes from the Semitic letter "Sāmek" and not "Šīn". In Etruscan and Latin, the /s/ value was maintained, and only in modern languages, S came to represent other sounds, like /S/ in Hungarian or /z/ in English, French and German (in English rise; in French lisez, "read! (imperative pl.)"; in German lesen "to read").
An archaic alternative form of s, ſ, called the long s or medial s, was used at the beginning or in the middle of the word; the modern form, the short or terminal s, was used at the end of the word. The ligature of ſs became the German ess-tsett ( ß ).
Sierra represents the letter S in the NATO phonetic alphabet.
S is also:
Two-letter combinations starting with S: