The Armenian language (classical: հայերէն; reformed: հայերեն [hɑjɛˈɾɛn] hayeren) occupies an independent branch of the Indo-European language tree. It is the official language of the Republic of Armenia and the Republic of Artsakh. It has historically been spoken throughout the Armenian Highlands and today is widely spoken in the Armenian diaspora. Armenian is written using the Armenian alphabet, introduced in 405 AD by Mesrop Mashtots. Armenian has developed since at least the time of the first Armenian dynasty (the Yervanduni dynasty, founded in the 6th century BC). Hellenistic influences during the Artashesian Dynasty (2nd century BC to 1st century CE) led to word borrowings from Greek and Latin. As the state language of the Arshakuni dynasty of Armenia (1st to 5th century CE) was Parthian, a large portion of Armenian vocabulary has been formed from Parthian borrowings. The earliest extant form of written Armenian is from the 5th century and is known as Classical Armenian (5th to 11th century); translations of the Bible and other religious texts during this period led to extensive word borrowings from Hebrew and Syriac. Middle Armenian (12th to 15th century) began with the establishment of the Armenian Kingdom of Cilicia in the 12th century and is marked by an increased influence of European languages on Armenian, particularly Old French (which had become the secondary language of the Cilician nobility) and Italian (which had become the secondary language of Cilician commerce). Middle Armenian is the first written form of Armenian to display Western-type voicing qualities. Early Modern Armenian (16th to 18th centuries) is a mix of Middle Armenian and an evolving, non-standardized literary Modern Armenian (in Constantinople, Venice, the Ararat plain, and the Persian Armenian communities, particularly New Julfa). As Armenian communities were spread across a large geographic area during this period, early Modern Armenian was influenced by the languages of host societies, with loan words being borrowed from Arabic, Turkish, Persian, Georgian, Latin, Greek, Italian, French, German, Polish, Hungarian, and Russian. At the turn of the twentieth century, the Armenian linguist Hrachia Acharian identified 31 spoken Armenian dialects and classified them into 3 branches (7 dialects of the "-oom" branch, loosely corresponding to Eastern Armenian dialects; 21 dialects of the "-gu" branch, loosely corresponding to Western Armenian dialects; and 3 dialects of the "-el" branch). The two standard forms of written Modern Armenian – Western Armenian and Eastern Armenian – began to take shape during the early to mid 19th century, with Constantinople in the Ottoman Empire being the center of literary Western Armenian, and Tiflis in the Russian Empire being the center of literary Eastern Armenian. The Armenian Genocide of 1915-1923 had a catastrophic impact on the Armenian population living in the Armenian homeland, with two-thirds of the total Armenian population being killed and nearly all of the remaining Armenian population living in the Ottoman Empire being expelled from their ancestral homeland; this had an especially catastrophic effect on the 21 Western Armenian dialects. While some survivors from the western regions of the Ottoman Empire fled as far as the United States, France, and South America, most fled south to Syria, Lebanon, Egypt, Jerusalem, Cyprus, and Iraq, with Beirut becoming the new center of literary Western Armenian. With the migration of survivors from eastern regions of the Ottoman Empire to the Russian Empire, the emergence of the Armenian Soviet Socialist Republic in 1922, and the migration of Armenian intellectuals of Tiflis to the new Republic, Yerevan became the new center of literary Eastern Armenian. Under Soviet rule, Eastern Armenian began to be heavily influenced by the Russian language, resulting in a large number of borrowings of not only technical words and neologisms, but also everyday words. Western Armenian, on the other hand, followed a more purist course, with writers and educational establishments making a conscious effort to use the Armenian counterparts of recent word borrowings from Turkish and Arabic. Various spelling reforms implemented in Soviet Armenia in the 1920s led to a further divide between the literary Eastern and literary Western Armenian languages, with the latter (and Eastern Armenian writers of Iran) continuing to use traditional Armenian orthography. Thus, today the two modern dialects of Armenian differ in their phonology, morphology, vocabulary, and orthography.