Urdu is an Indo-Aryan language spoken chiefly in South Asia. It is the official national language and lingua franca of Pakistan. In India, Urdu is an Eighth Schedule language whose status, function, and cultural heritage is recognized by the Constitution of India; it has some form of official status in several Indian states. In Nepal, Urdu is a registered regional dialect. Urdu has been described as a Persianised standard register of the Hindustani language. Urdu and Hindi share a common Indo-Aryan vocabulary base and very similar phonology and syntax, making them mutually intelligible in colloquial speech.
Urdu became a literary language in the 18th-century and two similar standard forms came into existence in Delhi and Lucknow; since 1947 a third standard has arisen in Karachi. Deccani, an older form used in the south, became a court language of the Deccan Sultanates in the 16th century.