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
Alphabet a new letter ՈՒ ու (which was a digraph before). The Armenian word for "alphabet" is "" (), named after the first two letters of the Armenian alphabet Ա այբ ayb and Բ բեն ben. The Armenian script's directionality is horizontal left-to-right, like the Latin and Greek alphabets. Alphabets often come to be associated with a standard ordering of their letters, which can then be used for purposes of collation—namely for the listing of words and other items in what is called "alphabetical order". The basic ordering of the Latin alphabet (A B C D E F G H I