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
Letter (alphabet) ⵕ, ⵙ, ⵚ, ⵜ, ⵟ, ⵡ, ⵢ, ⵣ, ⵥ. International Phonetic Alphabet - used to represent exact pronunciation. example, ʔ named Glottal Stop For other writing systems and their letters, see List of writing systems. Some writing systems have two major forms for each letter: an "uppercase" form (also called "capital" or "majuscule") and a "lowercase" form (also called "minuscule"). Only three Roman letters, "a", "g" and "t" , have more than one standard lowercase form. Upper- and lowercase letters represent the same sound, but serve different functions in writing. Capital letters are most often used at the beginning of