Urdu is an Indo-Aryan language and the national language of Pakistan, and is closely related to and mutually intelligible with Hindi, though a lot of Urdu vocabulary comes from Persian and Arabic, while Hindi contains more vocabulary from Sanskrit. Linguists consider Standard Urdu and Standard Hindi to be different formal registers both derived from the Khari Boli dialect, which is also known as Hindustani. At an informal spoken level there are few significant differences between Urdu and Hindi and they could be considered varieties a single language.
Except Pakistan & India, there are Urdu speaking in Afghanistan, Bahrain, Bangladesh, Botswana, Fiji, Germany, Guyana, Malawi, Mauritius, Nepal, Norway, Oman, Qatar, Saudi Arabia, South Africa, Thailand, the UAE, the UK and Zambia.
Urdu has been written with a version of the Perso-Arabic script since the 12th century and is normally written in Nastaliq style. The word Urdu is Turkish for 'foreign' or 'horde'.