History of the Greek alphabet retained the sound. A symbol based on the left-hand half ( ├ ) of the letter Η was therefore sometimes used to indicate the presence of where necessary, and its absence was indicated by a symbol based on the right half. During the classical period, ΕΙ came to be pronounced and ΟΥ came to be pronounced , Υ having meanwhile moved to . By about 200 BC, a system of diacritical marks was invented, representing the tone accents in use in Ancient Greek. This also helped to indicate the length of the vowels Α, Ι, and Υ in certain cases
Coptic alphabet of Greek origin; 6 or 7 more were retained from Demotic, depending on the dialect (6 in Sahidic, another each in Bohairic and Akhmimic). In addition to the alphabetic letters, the letter ϯ stood for the syllable or . As the Coptic alphabet is simply a typeface of the Greek alphabet, with a few added letters, it can be used to write Greek without any transliteration schemes. Latin equivalents would include the Icelandic alphabet (which likewise has added letters), or the Fraktur alphabet (which has distinctive forms). While initially unified with the Greek alphabet by Unicode, a proposal was later