The letter
eta (, , originally called
hēta) had two different functions, both derived from the name of its Phoenician model,
hēth: the majority of Greek dialects continued to use it for the consonant , similar to its Phoenician value (). However, the consonant was progressively lost from the spoken language (a process known as
psilosis), and in those dialects where this had already happened early on in the archaic period, was instead used to denote the long vowel , which occurred next in its name and was thus, in the -less dialects, its natural
acrophonic value. Early psilotic dialects include eastern
Ionic Greek, the
Aeolic Greek of
Lesbos, as well as the
Doric Greek of
Crete and
Elis. The distribution of vocalic and differs further between dialects, because the Greek language had a system of three distinct
e-like
phonemes: the long
open-mid (classical spelling ), the long
close-mid (classical spelling ), and the short vowel (classical spelling ). In the psilotic dialects of
Anatolia and adjacent eastern Aegean islands, as well as
Crete, vocalic was used only for . In a number of Aegean islands, notably
Rhodes,
Milos,
Santorini and
Paros, it was used both for and for without distinction. In
Knidos, a variant letter was invented to distinguish the two functions: was used for , and for . In south Italian colonies, especially
Taranto, after c. 400 BC, a similar distinction was made between for , and for . This latter symbol was later turned into the diacritic sign for
rough breathing by the Alexandrine grammarians. In
Naxos the system was slightly different: here, too, the same letter was used for and for a long vowel, but only in those cases where a long e-like sound had arisen through
raising from older , not – as other users of vocalic eta did – also for the older inherited from proto-Greek. This probably means that while in the dialects of other eta users the old and new long
e had already merged in a single phoneme, the raising sound in Naxos was still distinct both from and , hence probably an -like sound. Yet another distinction was found in a group of cities in the north-east of the
Peloponnese, most notably
Corinth: here, it was not the open-mid that was distinguished among the three
e-sounds, but the closed-mid . The normal letter epsilon () was used exclusively for the latter, while a new special symbol (or, in
Sicyon, ) stood both for short and for . Yet another variation of the system is found in neighbouring
Tiryns: it uses the letter forms of the Corinthian system, versus E, but with the functional values of the classic eta versus epsilon system. ==Archaic letters==