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
Sho (letter) was a survival or reintroduction of the archaic Greek letter San. It closely resembles, perhaps coincidentally, a letter of the Greek-based Carian alphabet which may have also stood for . The name "sho" was coined for the letter for purposes of modern computer encoding in 2002, on the basis of analogy with "rho" (ρ), the letter with which it seems to be graphically related. Ϸ was added to Unicode in version 4.0 (2003), in an uppercase and lowercase character designed for modern typography. Sho (letter) The letter (sometimes called sho or san) was a letter added to the Greek alphabet