The official language of Iran is Persian. Over half of Iranians speak a dialect of Persian. Arabic is widely spoken, but it is not usually the first language before 1979. European languages were taught in schools.
Most literature and religious texts are written in Arabic. Alongside Persian(the official language) there are many other languages which are spoken by some Iranian people all around the country.
There is a big population of Azeri language speakers, and Kurdish, Lurish, Gilaki, Mazandarani, Turkmeni, Balouchi, Tati and Talyshi and khazi Arabic speaking people.
1.https://www.quora.com/What-languages-are-spoken-in-Iran
2. https://www.britannica.com/topic/Iranian-languages