Language
During the Rashidun Caliphate, the official language of Persia remained Persian, just as the official languages of Syria and Egypt remained Greek and Coptic. However, during the Ummayad Caliphate, the Ummayads imposed Arabic as the primary language of their subjected people throughout their empire, displacing their indigenous languages. Although an area from Iraq to Morocco speaks Arabic to this day, Middle Persian proved to be much more enduring. Most of its structure and vocabulary survived, evolving into the modern Persian language. However, Persian did incorporate a certain amount of Arabic vocabulary, especially words pertaining to religion, and it switched from the Pahlavi Aramaic alphabet to a modified version of the Arabic alphabet.
Read more about this topic: Muslim Conquest Of Persia