Urdu is a register of Hindi-Urdu, identified with Muslims in South Asia. Urdu is the national language and lingua franca of Pakistan. It is also widely spoken in India, where it is one of the 22 scheduled languages and an official language of five states. Based on the Khariboli dialect of Delhi, Urdu developed under the influence of Persian, Arabic, and Turkic over the course of almost 900 years. It began to take shape in what is now Uttar Pradesh, India during the Delhi Sultanate (1206–1527), and continued to develop under the Mughal Empire (1526–1858). Urdu is mutually intelligible with Standard Hindi spoken in India. Both languages share the same Indic base and are so similar in phonology and grammar that they appear to be one language. The combined population of Hindi and Urdu speakers is the fourth largest in the world.