Latin or Roman script is a set of graphic signs (script) based on the letters of the classical Latin alphabet. This is derived from a form of the Cumaean Greek version of the Greek alphabet used by the Etruscans. Several Latin-script alphabets exist, which differ in graphemes, collation and phonetic values from the classical Latin alphabet. The Latin script is the basis of the International Phonetic Alphabet and the 26 most widespread letters are the letters contained in the ISO basic Latin alphabet. 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 percent of the world's population). Latin script is used as the standard method of writing in most Western, Central, as well as in some Eastern European languages, as well as in many languages in other parts of the world.