Hindustani (hĭndōstänˈē) [key], subdivision of the Indic group of the Indo-Iranian languages, which themselves form a subfamily of the Indo-European family of languages. Some authorities define Hindustani as the spoken form of Hindi and Urdu. Others prefer to call Hindi and Urdu written varieties of Hindustani. The term Hindustani can also be used to include some vernacular dialects of northern India. Hindi is the variety of Hindustani used by Hindus; it is also the official language of India. Written in the Devanagari alphabet employed for Sanskrit, Hindi is read from left to right and has a vocabulary that is strictly Indic. Urdu, on the other hand, is the form of Hindustani used by Muslims and is official in Pakistan; it is written in a modified form of the Arabic alphabet, is read from right to left, and has added a number of words borrowed from Arabic and Persian to its originally Indic vocabulary. Despite these differences, both Hindi and Urdu are written variants of the same Indic subdivision, Hindustani. The latter goes back to the Prakrits or vernacular dialects of classical Sanskrit (see Indo-Iranian) and has been greatly influenced by Sanskrit itself. The grammar of Hindustani is much simpler than that of the older Indic tongues, such as Sanskrit. For instance, the neuter gender, the dual number, and the old case endings for the noun have been discarded. The conjugation of the verb has also been greatly simplified. Instead of prepositions, Hindustani uses postpositions, or particles placed after words to make clear their grammatical function or relationship. Hindustani plays an important role in modern India as a lingua franca; the number of people who speak or understand Hindustani in India and Pakistan has been variously estimated, but it probably exceeds 400 million persons. Thus Hindustani ranks third in number of speakers, after Chinese and English, among the world's language communities.
See G. H. Fairbanks and B. G. Misra, Spoken and Written Hindi (1966); A. Rai, A House Divided: The Origin and Development of Hindi-Hindavi (1985).