Dari (Persian: دری [dæˈɾiː]) or Dari Persian (Persian: فارسی دری [fɒːɾsije dæˈɾiː]) is the variety of the Persian language spoken in Afghanistan. Dari is the term officially recognized and promoted since 1964 by the Afghan government for the Persian language. Hence, it is also known as Afghan Persian in many Western sources.
As defined in the Constitution of Afghanistan, it is one of the two official languages of Afghanistan; the other is Pashto. Dari is the most widely spoken language in Afghanistan and the native language of approximately 50% of the population, serving as the country's lingua franca. The Iranian and Afghan types of Persian are highly mutually intelligible, with differences found primarily in the vocabulary and phonology.
Originally, Dari was the name given to the Old Persian language at a very early date and widely attested in Arabic and Persian texts since the 10th century. In historical usage, Dari refers to the Middle Persian court language of the Sassanids. By way of Early New Persian, Dari Persian, like Iranian Persian and Tajik, is a continuation of Middle Persian, the official religious and literary language of the Sassanian Empire (224–651 CE), itself a continuation of Old Persian, the language of the Achaemenids (550–330 BC). In historical usage, Dari refers to the Middle Persian court language of the Sassanids.