Hindi is an Indo-Aryan language spoken chiefly in the Hindi Belt region encompassing parts of northern, central, eastern, and western India. Hindi has been described as a standardized and Sanskritised register of the Hindistani language, which itself is based primarily on the Khariboli dialect of Delhi and neighboring areas of North India. Hindi, written in the Devanagari script, is one of the two official languages of the Government of India, along with English. It is an official language in nine states and three union territories and an additional official language in three other states. Hindi is also one of the 22 scheduled languages of the Republic of India.

Hindi is the lingua franca of the Hindi Belt. It is also spoken, to a lesser extent, in other parts of India (usually in a simplified or pidginized variety such as Bazaar Hindistani 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, such as Awadhi and Bhojpuri. Such languages include Fiji Hindi, which has an official status in Fiji, and Caribbean Hindistani, which is spoken in Trinidad and Tobago, Guyana, and Suriname. Apart from the script and formal vocabulary, standard Hindi is mutually intelligible with standard Urdu, another recognized register of Hindistani as both share a common colloquial base.

Hindi is the fourth most-spoken first language in the world, after Mandarin, Spanish and English.