The impact of Islam on Indian culture has been inestimable. It permanently influenced the development of all areas of human endeavour – language, dress, cuisine, all the art forms, architecture and urban design, and social customs and values. Conversely, the languages of the Muslim invaders were modified by contact with local languages, to Urdu, which uses the Arabic script. This language was also known as Hindustani, an umbrella term used for the vernacular terminology of Hindi as well as Urdu, both major languages in South Asia today derived primarily from Sanskrit grammatical structures and vocabulary.