Latin script, or Roman script, is a set of graphic signs (script) based on the letters of the classical Latin alphabet, a form of the Cumaean Greek version of the Greek alphabet. It is used as the standard method of writing in most Western and Central European languages, as well as many languages from other parts of the world. Latin script is the basis for the largest number of alphabets of any writing system and is the most widely adopted writing system in the world (commonly used by about 70% of the world's population). It is also the basis of the International Phonetic Alphabet. The 26 most widespread letters are the letters contained in the ISO basic Latin alphabet.