The Armenian language (or հայերեն, pronounced [hɑjɛˈɾɛn]) is of great interest to linguists for its distinctive phonological developments within the Indo-European family of languages. Armenian has its own unique script – the Armenian alphabet – invented in 405–406 AD by the ancient linguist and cleric Mesrop Mashtots. The Old Armenian was the only written form of the language from the 5th to the 19th century but meanwhile two dialects have gradually distinguished themselves: Eastern and Western. However, only the Eastern dialect is taught as the written form at school nowadays, even though the Western dialect is more widely spoken. Writing system: Armenian alphabet Official language in: Armenia; Nagorno-Karabakh Republic