Pashto is a member of the southeastern Iranian branch of Indo-Iranian languages spoken in Afghanistan, Pakistan and Iran. There are three main varieties of Pashto: Northern Pashto, spoken mainly in Pakistan; Southern Pashto, spoken mainly in Afghanistan; and Central Pashto, spoken mainly in Pakistan.

Persian is an Iranian language within the Indo-Iranian branch of the Indo-European languages. It is primarily spoken in Iran, Afghanistan , Tajikistan, and countries which historically came under Persian influence. The Persian language is classified as a continuation of Middle Persian, the official religious and literary language of Sassanid Iran, itself a continuation of Old Persian, the language of the Persian Empire in the Achaemenid era.