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
History of the Greek alphabet and "qōph" represented sounds that were not distinctive in Greek—at most, they may have been identified with allophones determined by the following vowel. The letter qoppa was used in certain Greek dialects (notably the western dialects, which ultimately gave rise to Etruscan and eventually the Latin alphabet), but elsewhere dropped out of general use. It is possible that qoppa had been assigned to the Ancient Greek , and when that sound shifted to , the letter qoppa continued as the letter phi. Phoenician had three letters, "sāmekh, ṣādē" and "šin", representing three or probably four voiceless sibilant sounds, whereas Greek