Hindi (Devanagari: हिन्दी, IAST: Hindī), or Modern Standard Hindi (Devanagari: मानक हिन्दी, IAST: Mānak Hindī) is a standardised and Sanskritised register of the Hindustani language.
Along with the English language, Hindi written in the Devanagari script is the official language of the Government of India. On 14 September 1949, the Constituent Assembly of India adopted Hindi written in Devanagari script as the official language of the Republic of India. To this end, several stalwarts rallied and lobbied pan-India in favor of Hindi, most notably Beohar Rajendra Simha along with Hazari Prasad Dwivedi, Kaka Kalelkar, Maithili Sharan Gupt and Seth Govind Das who even debated in Parliament on this issue. As such, on the 50th birthday of Beohar Rajendra Simha on 14 September 1949, the efforts came to fruition following adoption of Hindi as the official language. It is one of the 22 scheduled languages of the Republic of India. However, it is not yet the national language of Indiabecause it was not prescribed as such in the Indian constitution.
Hindi is the lingua franca of the so-called Hindi belt in India. Outside India, it is an official language which is known as Fiji Hindi in Fiji, and is a recognised regional language in Mauritius, Trinidad and Tobago, Guyana, and Suriname. Apart from specialized vocabulary, Hindi is mutually intelligible with Standard Urdu, another recognized register of Hindustani.
Individually, as a linguistic variety, Hindi is the fourth most-spoken first language in the world, after Mandarin, Spanish and English. Alongside Urdu as Hindustani, it is the third most-spoken language in the world, after Mandarin and English.