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
History of the Greek alphabet of an upright and less ornamented style of writing more like Latin print. In 1982, the monotonic orthography was officially adopted, abandoning the rough and smooth breathings (since the sound had long since disappeared) and reducing the three types of accent mark to one (since the tone accent had been replaced by a stress accent). Greek pronunciation has also changed considerably since ancient times, but these changes have not been apparent from the orthography, which has remained conservative — see Greek alphabet for a summary of the current situation. The names of some letters were changed in order to distinguish