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. Hindi is an Indo-Germanic or Indo-European language. It is descended from Sanskrit and is considered part of the New Indo-Aryan subgroup. However, it was also influenced, especially in vocabulary, by various other languages including Persian, Arabic, Turkish, Portuguese, and English. 
Along with the English language, Hindi written in the Devanagari script is the official language of the Government of India. It is also one of the 22 scheduled languages of the Republic of India. However, it is not the national language of India because 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.
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.