Greek alphabet glottal ("heth") was borrowed in two different functions by different dialects of Greek: as a letter for /h/ (Η, heta) by those dialects that had such a sound, and as an additional vowel letter for the long (Η, eta) by those dialects that lacked the consonant. Eventually, a seventh vowel letter for the long (Ω, omega) was introduced. Greek also introduced three new consonant letters for its aspirated plosive sounds and consonant clusters: Φ ("phi") for , Χ ("chi") for and Ψ ("psi") for . In western Greek variants, Χ was instead used for and Ψ for . The origin
Coptic alphabet accepted to separate it, with the proposal noting that Coptic is never written using modern Greek letter-forms (unlike German, which may be written with Fraktur or Roman Antiqua letter-forms), and that the Coptic letter-forms have closer mutual legibility with the Greek-based letters incorporated into the separately encoded Cyrillic alphabet than with the forms used in modern Greek. In Old Coptic, there were a large number of Demotic Egyptian characters, including some logograms. They were soon reduced to half a dozen, for sounds not covered by the Greek alphabet. The following letters remained: In Unicode, most Coptic letters formerly shared codepoints