By the end of the 4th century BC, it had displaced local alphabets across the Greek-speaking world to become the standard form of the Greek alphabet. Because of Eucleides's role in suggesting the idea to adopt the Ionian alphabet, the standard twenty-four-letter Greek alphabet is sometimes known as the "Eucleidean alphabet". The classical twenty-four-letter alphabet that is now used to represent the Greek language was originally the local alphabet of Ionia. Epichoric alphabets are commonly divided into four major types according to their different treatments of additional consonant letters for the aspirated consonants (/pʰ, kʰ/) and consonant clusters (/ks, ps/) of Greek.
The Greek alphabet has been used to write the Greek language since the late 9th or early 8th century BC.
Among the vowel letters, Modern Greek sound values reflect the radical simplification of the vowel system of post-classical Greek, merging multiple formerly distinct vowel phonemes into a much smaller number. 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 international technical symbols and labels in many domains of mathematics, science, and other fields. Sound values and conventional transcriptions for some of the letters differ between Ancient and Modern Greek usage because the pronunciation of Greek has changed significantly between the 5th century BC and the present. It was derived from the earlier Phoenician alphabet, and is the earliest known alphabetic script to systematically write vowels as well as consonants. To write polytonic Greek, one may use combining diacritical marks or the precomposed characters in the "Greek Extended" block (U+1F00 to U+1FFF).
Digraphs and letter combinations
- Apart from the daughter alphabets listed above, which were adapted from Greek but developed into separate writing systems, the Greek alphabet has also been adopted at various times and in various places to write other languages.
- The Greek alphabet has been used to write the Greek language since the late 9th or early 8th century BC.
- For the range A0–FF (hex), it follows the Unicode range 370–3CF (see below) except that some symbols, like ©, ½, § etc. are used where Unicode has unused locations.
- These four types are often conventionally labelled as "green", "red", "light blue" and "dark blue" types, based on a colour-coded map in a seminal 19th-century work on the topic, Studien zur Geschichte des griechischen Alphabets by Adolf Kirchhoff (1867).
The vowel letters ⟨α, η, ω⟩ carry an additional diacritic in certain words, the so-called iota subscript, which has the shape of a small vertical stroke or a miniature ⟨ι⟩ below the letter. The acute accent in aulós avˈlos ('flute') distinguishes the word from its homograph áulos ˈailos ('immaterial'). In other countries, students of Ancient Greek may use a variety of conventional approximations of the historical sound system in pronouncing Ancient Greek. As a consequence, the spellings of words in Modern Greek are often not predictable from the pronunciation alone, while the reverse mapping, from spelling to pronunciation, is usually regular and predictable.
Sound values
For the range A0–FF (hex), it follows the Unicode range 370–3CF (see below) except that some symbols, like ©, ½, § etc. are used where Unicode has unused locations. Some letters can occur in variant shapes, mostly inherited from medieval minuscule handwriting. Each of these is still a "chapter Letter", albeit a double-digit letter just as 10 through 99 are double-digit numbers.
The letter ⟨ε⟩ was called e psilon ("plain e") to distinguish it from the identically pronounced digraph ⟨αι⟩, while, similarly, ⟨υ⟩, which at this time was pronounced y, was called y psilon ("plain y") to distinguish it from the identically pronounced digraph ⟨οι⟩. Thus, the letters ⟨ο⟩ and ⟨ω⟩, pronounced identically by this time, were called o mikron ("small o") and o mega ("big o"). These four types are often conventionally labelled as "green", "red", "light blue" and "dark blue" types, based on a colour-coded map in a seminal 19th-century work on the topic, Studien zur Geschichte des griechischen Alphabets by Adolf Kirchhoff (1867). When it ταβερνα ο κωστασ παιανια was adopted for writing Greek, certain consonants were adapted in order to express vowels. During the Mycenaean period, between roughly the 16th and 12th centuries BC, a script called Linear B was used to write the earliest attested form of the Greek language, known as Mycenaean Greek. The form in which classical Greek names are conventionally rendered in English goes back to the way Greek loanwords were incorporated into Latin in antiquity.
In the following group of consonant letters, the older forms of the names in Ancient Greek were spelled with -εῖ, indicating an original pronunciation with -ē. Here too, the changes in the pronunciation of the letter names between Ancient and Modern Greek are regular. In the cases of the three historical sibilant letters below, the correspondence between Phoenician and Ancient Greek is less clear, with apparent mismatches both in letter names and sound values. The name of lambda is attested in early sources as λάβδα besides λάμβδα; in Modern Greek the spelling is often λάμδα, reflecting pronunciation. When the Greeks adopted the Phoenician alphabet, they took over not only the letter shapes and sound values but also the names by which the sequence of the alphabet could be recited and memorized.
Many symbols have traditional uses, such as lower case epsilon (ε) for an arbitrarily small positive number, lower case pi (π) for the ratio of the circumference of a circle to its diameter, capital sigma (Σ) for summation, and lower case sigma (σ) for standard deviation. Apart from the daughter alphabets listed above, which were adapted from Greek but developed into separate writing systems, the Greek alphabet has also been adopted at various times and in various places to write other languages. Some dialects of the Aegean and Cypriot have retained long consonants and pronounce ˈɣamːa and ˈkapʰa; also, ήτα has come to be pronounced ˈitʰa in Cypriot.
Greek symbols are used as symbols in mathematics, physics and other sciences. In the 9th and 10th centuries, uncial book hands were replaced with a new, more compact writing style, with letter forms partly adapted from the earlier cursive. Such handwriting has been preserved especially from papyrus manuscripts in Egypt since the Hellenistic period. Besides the upright, straight inscriptional forms (capitals) found in stone carvings or incised pottery, more fluent writing styles adapted for handwriting on soft materials were also developed during antiquity. This distinction is an innovation of the modern era, drawing on different lines of development of the letter shapes in earlier handwriting.
Different chapters within the same fraternity are almost always (with a handful of exceptions) designated using Greek letters as serial numbers. Sometimes early fraternal organizations were known by their Greek letter names because the mottos that these names stood for were secret and revealed only to members of the fraternity. The name of this fraternal organization is an acronym for the ancient Greek phrase Φιλοσοφία Βίου Κυβερνήτης (Philosophia Biou Kybernētēs), which means "Love of wisdom, the guide of life" and serves as the organization's motto. In North America, many college fraternities and sororities are named with combinations of Greek letters, and are hence also known as "Greek letter organizations". To mark a letter as a numeral sign, a small stroke called keraia is added to the right of it.
Among consonant letters, all letters that denoted voiced plosive consonants (/b, d, g/) and aspirated plosives (/pʰ, tʰ, kʰ/) in Ancient Greek stand for corresponding fricative sounds in Modern Greek. In both Ancient and Modern Greek, the letters of the Greek alphabet have fairly stable and consistent symbol-to-sound mappings, making pronunciation of words largely predictable. Additionally, Modern and Ancient Greek now use different diacritics, with ancient Greek using the polytonic orthography and modern Greek keeping only the stress accent (acute) and the diaeresis.
For a time, a writing style with alternating right-to-left and left-to-right lines (called boustrophedon, literally 'ox-turning', after the manner of an ox ploughing a field) was common, until in the classical period the left-to-right writing direction became the norm. For a number of letters, sound values differ considerably between Ancient and Modern Greek, because their pronunciation has followed a set of systematic phonological shifts that affected the language in its post-classical stages. The Roman alphabet has a similar extended form with such double-digit letters when necessary, but it is used for columns in a table or chart rather than chapters of an organization. In an organization that expands to more than 24 chapters, the chapter after Ω chapter is AA chapter, followed by AB chapter, etc. As an organization expands, it establishes a B chapter, a Γ chapter, and so on and so forth.