This is the Western Iranian language that belongs to the Iranian branch of the Indo-Iranian subdivision of the Indo-European languages. Persian or Farsi is the official language of Iran, and two varieties of Persian known as Dari and Tajik are the official languages in Afghanistan and Tajikistan.

The old Persian was spoken until the third century BCE. Written in Arabic characters, Modern Persian also has many Arabic loanwords and an extensive literature. Modern Persian grammar is in many ways much simpler than its old forms, having lost most of the inflectional systems of the older varieties of Persian.