Languages of Iran
First Aramaic and then Arabic had considerable contact with Iranian languages. Their impact differs. Aramaic was made the official language of communication by Achaemenid ruler Darius the Great, and hence is referred to as Imperial Aramaic, which considerably contributed to the success of the empire. It initiated a literary tradition that continued into Middle Iranian times, finally to be replaced by the various literary languages. Aramaic dialects continued to be spoken in the northwestern regions of Iran by small Christian and Jewish communities, and left their reflexes in the local Jewish-Iranian dialects and local varieties of Judeo-Persian. By contrast, Arabic had become the new administrative and religious-scientific superstrate language after the conquest of Persia in the mid-7th century, when Arabic tribes and administrative groups began to settle throughout Greater Iran for some three hundred years. Of these, only few pockets have remained in eastern and southern Persia, and until recently they had remained virtually unstudied.