Greek orthography has used a variety of diacritics starting in the Hellenistic period. The complex polytonic orthography which notated Ancient Greek phonology was used until 1982, when it was supplanted by the simplified monotonic orthography, which corresponds to Modern Greek phonology, and requires only two diacritics.
In the polytonic system, the acute accent ( ´ ), the grave accent ( ` ), and the circumflex ( ˆ ) or tilde ( ˜ ) indicate different kinds of pitch accents. The spiritus asper ( ῾ ) indicates aspiration (the presence of an /h/ sound), while the spiritus lenis ( ᾿ ) indicates a lack of aspiration. It is said to have been introduced by Aristophanes of Byzantium around 200 BC, and was the standard orthography for all varieties of Greek from Hellenistic times until 1982, although the distinctions it represented had disappeared from the spoken language early in the Christian era. Since the pitch accent eventually gave place to a dynamic accent, and aspiration was lost in Greek, most polytonic diacritics have no phonetic significance in the modern language, merely reflecting ancient Greek etymology.
The monotonic orthography (μονός = single + τόνος = accent) is the simplified spelling introduced in 1982 for modern Greek. It replaced all accent marks with just one, the acute, and abandoned the use of the breathings. The diaeresis ( ¨ ) remained in use to indicate a hiatus: compare modern Greek παϊδάκια [paiðaca] (lamb chops) and παιδάκια [peðaca] (little children). The traditional system is called polytonic orthography to distinguish it from the monotonic one.
| Πάτερ ἡμῶν ὁ ἐν τοῖς οὐρανοῖς· ἁγιασθήτω τὸ ὄνομά σου·|
ἐλθέτω ἡ βασιλεία σου·
γενηθήτω τὸ θέλημά σου, ὡς ἐν οὐρανῷ, καὶ ἐπὶ τῆς γῆς·
τὸν ἄρτον ἡμῶν τὸν ἐπιούσιον δὸς ἡμῖν σήμερον·
καὶ ἄφες ἡμῖν τὰ ὀφειλήματα ἡμῶν, ὡς καὶ ἡμεῖς ἀφίεμεν τοῖς ὀφειλέταις ἡμῶν·
καὶ μὴ εἰσενέγκῃς ἡμᾶς εἰς πειρασμόν, ἀλλὰ ῥῦσαι ἡμᾶς ἀπὸ τοῦ πονηροῦ.
| Πάτερ ημών ο εν τοις ουρανοίς· αγιασθήτω το όνομά σου·|
ελθέτω η βασιλεία σου·
γενηθήτω το θέλημά σου, ως εν ουρανώ, και επί της γης·
τον άρτον ημών τον επιούσιον δος ημίν σήμερον·
και άφες ημίν τα οφειλήματα ημών, ως και ημείς αφίεμεν τοις οφειλέταις ημών·
και μη εισενέγκης ημάς εις πειρασμόν, αλλά ρύσαι ημάς από του πονηρού.
Polytonic Greek utilizes a set of diacritics on certain letters, illustrated below using the letter α. (Note that the transliteration of the names of the diacritics into the Latin alphabet varies, chiefly depending on whether they are considered words from Classical or Modern Greek.)
All of these diacritics are important in Classical Greek (and the breathings in particular are relevant to the etymology of words in other languages), but except for the diaeresis and the acute accent none have any significance in the modern language: there is no difference in pronunciation between words which formerly had smooth and rough breathings, and the pitch accent has been replaced with a stress accent.
The original Greek alphabet did not have any diacritics. The Greek alphabet is attested since the 8th century BC. Until 403 BC, variations of the Greek alphabet—which used capitals exclusively—were used in different cities and areas. From 403 on, the Athenians decided to employ a version of the Ionian alphabet. With the spread of Koine Greek, a continuation of the Attic dialect, the Ionic alphabet superseded more or less quickly the other alphabets, called epichoric. The Ionian alphabet, however, was also made up only of capitals.
The rough and smooth breathings were introduced in classical times in order to represent the presence or absence of an /h/ in Attic Greek, which had adopted a form of the alphabet in which the letter H was no longer available for this purpose as it was used to represent the long vowel /εː/.
During the Hellenistic period, (3rd century BC), Aristophanes of Byzantium introduced the breathings — marks of aspiration (the aspiration however being already noted on certain inscriptions, not by means of diacritics but by regular letters or modified letters) and the accents, of which the use started to spread, to become standard in the Middle Ages. It wasn’t until the 2nd century AD that the accents and breathings appeared sporadically in the papyruses. The need for the diacritics arose from the gradual divergence between spelling and pronunciation.
The majuscule system written entirely in capital letters was used until the 8th century, when the minuscule polytonic supplanted it. The modern convention, by which an acute accent on the last syllable of a word becomes a grave accent, was devised in Byzantine times, after the accent became stress; the convention began with certain proclitic words, which lose their accent before another word, and was generalized.
In the later development of the language, the ancient pitch accent were replaced by an intensity accent making the differences among accents superfluous, and the /h/ sound became silent.
At the beginning of the 20th century (official since the 1960s), the grave was replaced by the acute and the iota subscript and the breathings on the rho were abolished, except in printed texts. Greek typewriters from that era did not have keys for the grave accent or the iota subscript, and these diacritics were also not taught in primary schools where instruction was in Demotic.
Following the official adoption of the Demotic form of the language, the monotonic orthography was imposed by law in 1982. The latter uses only the acute accent (or sometimes a vertical bar intentionally distinct from any of the traditional accents) and diaeresis and omits the breathings. This simplification has been criticized on the grounds that polytonic orthography provides a cultural link to the past. Some individuals, institutions, and publishers continue to prefer the polytonic system, though an official reintroduction of the polytonic system does not seem probable. The Greek Orthodox church, for example, continues to use polytonic orthography, and some books and the daily newspaper Ἑστία are still published in polytonic, especially those few still written in katharevousa. Though the polytonic system was not used in Classical Greece, these critics argue that modern Greek, as a continuation of Byzantine and post-medieval Greek, should continue their writing conventions.
Some textbooks of Ancient Greek for foreigners have retained the breathings, but dropped all the accents, simplifying the task for the learner, but breaking the link with the modern language.
While the tónos of monotonic orthography looks similar to the oxeîa of polytonic orthography in most fonts, Unicode has historically had separate symbols for letters with these diacritics. For example, the monotonic "Greek small letter alpha with tónos" is at U+03AC, while the polytonic "Greek small letter alpha with oxeîa" is at U+1F71. The monotonic and polytonic accent however have been de jure equivalent since 1986, and accordingly the oxeîa diacritic in Unicode decomposes canonically to the monotonic tónos — both are underlyingly treated as equivalent to the Latin acute accent, U+0301.
The following tables list some of the characters required in polytonic Greek.
|Basic vowels||Vowels with iota subscript||Rho|
|Smooth and acute||ἄ||ἔ||ἤ||ἴ||ὄ||ὔ||ὤ||ᾄ||ᾔ||ᾤ|
|Smooth and grave||ἂ||ἒ||ἢ||ἲ||ὂ||ὒ||ὢ||ᾂ||ᾒ||ᾢ|
|Smooth and circumflex||ἆ||ἦ||ἶ||ὖ||ὦ||ᾆ||ᾖ||ᾦ|
|Rough and acute||ἅ||ἕ||ἥ||ἵ||ὅ||ὕ||ὥ||ᾅ||ᾕ||ᾥ|
|Rough and grave||ἃ||ἓ||ἣ||ἳ||ὃ||ὓ||ὣ||ᾃ||ᾓ||ᾣ|
|Rough and circumflex||ἇ||ἧ||ἷ||ὗ||ὧ||ᾇ||ᾗ||ᾧ|
|Basic vowels||Vowels with iota subscript or adscript||Rho|
|Smooth and acute||Ἄ||Ἔ||Ἤ||Ἴ||Ὄ||Ὤ||ᾌ||ᾜ||ᾬ|
|Smooth and grave||Ἂ||Ἒ||Ἢ||Ἲ||Ὂ||Ὢ||ᾊ||ᾚ||ᾪ|
|Smooth and circumflex||Ἆ||Ἦ||Ἶ||Ὦ||ᾎ||ᾞ||ᾮ|
|Rough and acute||Ἅ||Ἕ||Ἥ||Ἵ||Ὅ||Ὕ||Ὥ||ᾍ||ᾝ||ᾭ|
|Rough and grave||Ἃ||Ἓ||Ἣ||Ἳ||Ὃ||Ὓ||Ὣ||ᾋ||ᾛ||ᾫ|
|Rough and circumflex||Ἇ||Ἧ||Ἷ||Ὗ||Ὧ||ᾏ||ᾟ||ᾯ|