English pronunciation of Greek letters

Greek alphabet
Type	Alphabet
Languages	Greek
Time period	c. 800 BCE – present
Parent systems	Egyptian hieroglyphs Proto-Sinaitic alphabet Phoenician alphabet Greek alphabet
Child systems	Gothic Glagolitic Cyrillic Coptic Armenian Old Italic Latin Georgian
Direction	Left-to-right
ISO 15924	Grek, 200
Unicode alias	Greek
Unicode range	U+0370–U+03FF Greek and Coptic U+1F00–U+1FFF Greek Extended

The Greek alphabet has been used to write the Greek language since the late 9th century BC or early 8th century BC It was derived from the earlier Phoenician alphabet, and was the first alphabetic script to have distinct letters for vowels as well as consonants. It is the ancestor of the Latin and Cyrillic scripts. Apart from its use in writing the Greek language, in both its ancient and its modern forms, the Greek alphabet today also serves as a source of technical symbols and labels in many domains of mathematics, science and other fields.

In its classical and modern forms, the alphabet has 24 letters, ordered from alpha to omega. Like Latin and Cyrillic, Greek originally had only a single form of each letter; it developed the letter case distinction between upper-case and lower-case forms in parallel with Latin during the modern era.

Sound values and conventional transcriptions for some of the letters differ between Ancient Greek and Modern Greek usage, because the pronunciation of Greek has changed significantly between the 5th century BC and today. Modern and Ancient Greek use different diacritics. The traditional orthography, which is used for Ancient Greek and sometimes for Modern Greek, has many diacritics, such as accent marks for pitch accent ("polytonic"), the breathing marks for the presence and absence of the initial /h/ sound, and the iota subscript for the final historical /i/ sound. In standard Modern Greek spelling, orthography has been simplified to the monotonic system, which uses only two diacritics: the acute accent and diaeresis.