Book excerpt: Urdu language, member of the Indo-Aryan group within the Indo-European family of languages. Urdu is spoken by more than 100 million people, predominantly in Pakistan and India. It is the official state language of Pakistan and is also officially recognized, or "scheduled," in the constitution of India. Significant speech communities exist in the United Arab Emirates, the United Kingdom, and the United States as well. Notably, Urdu and Hindi are mutually intelligible.Urdu developed in the 12th century CE from the regional Apabhramsha of northwestern India, serving as a linguistic modus vivendi after the Muslim conquest. Its first major poet was Amir Khosrow (1253-1325), who composed Dohas (couplets), folk songs, and riddles in the newly formed speech, then called Hindvi. This mixed speech was variously called Hindvi, Zaban-e-Hind, Hindi, Zaban-e-Delhi, Rekhta, Gujari, Dakkhani, Zaban-e-Urdu-e-Mualla, Zaban-e-Urdu, or just Urdu, literally 'the language of the camp.' Major Urdu writers continued to refer to it as Hindi or Hindvi until the beginning of the 19th century, although there is evidence that it was called Hindustani in the late 17th century (Hindustani now refers to a simplified speech form that is India's largest lingua franca).Urdu is closely related to Hindi, a language that originated and developed in the Indian subcontinent. They share the same Indic base and are so similar in phonology and grammar that they appear to be one language. In terms of lexicon, however, they have borrowed extensively from different sources--Urdu from Arabic and Persian, Hindi from Sanskrit--so they are usually treated as independent languages. Their distinction is most marked in terms of writing systems: Urdu uses a modified form of Perso-Arabic script, while Hindi uses Devanagari.