Hindi is an Indo-Aryan language with about 545 million speakers, 425 million of whom are native speakers. It is one of the official languages of India and is the main language used in the northern states of Rajasthan, Delhi, Haryana, Uttarakhand, Uttar Pradesh, Madhya Pradesh, Chhattisgarh, Himachal Pradesh, Jharkhand and Bihar, and is spoken in much of north and central India alongside other languages such as Punjabi, Gujarati, Marathi or Bengali. In other parts of India, as well as in Nepal, Bangladesh and Pakistan, Hindi is understood, and there is a significant number of Hindi speakers in South Africa, Mauritius, Fiji, Suriname, Guyana, Trinidad & Tobago and Nepal. In Fiji people of Indian origin speak Hindi, and in some areas the Fijian people also speak it.

Hindi is closely related to Urdu, the main language of Pakistan, which is written with the Arabic script, and linguists consider Standard Hindi and Standard Urdu to be different formal registers both derived from the Khari Boli dialect, which is also known as Hindustani. Apart from the difference in writing systems, the other main difference between Hindi and Urdu is that Hindi contains more vocabulary from Sanskrit, while Urdu contains more vocabulary from Persian. At an informal spoken level there are few significant differences between Urdu and Hindi and they could be considered varieties a single language.

Hindi first started to be used in writing during the 4th century AD. It was originally written with the Brahmiscript but since the 11th century AD it has been written with the Devanāgarī alphabet. The first printed book in Hindi was John Gilchrist’s Grammar of the Hindoostanee Language which was published in 1796.