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, which is catogorized under Aryan languages. In India, the official standardized variety of the language is based primarily on the Khariboli dialect of Delhi and other nearby areas of northern India. Hindi, written in the Devanagari script, is one of the two official languages of the Government of India, along with the English language. It is one of the 22 scheduled languages of the Republic of India. Contrary to the popular belief, Hindi is not the national language of India because no language was given such a status in the Indian constitution.
Hindi is the lingua franca of the Hindi belt and to a lesser extent other parts of India (usually in a simplified or pidginized variety such as Bazaar Hindustani or Haflong Hindi). Outside India, several other languages are recognized officially as “Hindi” but do not refer to the Standard Hindi language described here and instead descend from other dialects of Hindustani, such as Awadhi and Bhojpuri. Such languages include Fiji Hindi, which is official in Fiji, and Caribbean Hindustani, which is a recognized language in Trinidad and Tobago, Guyana, and Suriname. Apart from specialized vocabulary, spoken Hindi is mutually intelligible with standard Urdu, another recognized register of Hindustani.
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.