Page "Alphabet" Paragraph 1

A true alphabet has letters for the vowels of a language as well as the consonants.

The first " true alphabet " in this sense is believed to be the Greek alphabet, which is a modified form of the Phoenician alphabet.

In other types of alphabet either the vowels are not indicated at all, as was the case in the Phoenician alphabet ( such systems are known as abjads ), or else the vowels are shown by diacritics or modification of consonants, as in the devanagari used in India and Nepal ( these systems are known as abugidas or alphasyllabaries ).