Hindi, or more precisely Modern Standard Hindi and also known as Manak Hindi, High Hindi, Nagari Hindi, and Literary Hindi, is a standardised and sanskritised register of the Hindi-Urdu language. It is the native language of people living in Delhi, Haryana, Western Uttar Pradesh, northeastern Madhya Pradesh, and parts of eastern Rajasthan, and is one of the official languages of the Republic of India. But many non-native speakers from other parts of India, too, understand it easily because it is close to their native languages that, just like Hindi, originated from Sanskrit. These languages have common roots and the native speakers of several regional Indian languages find it easier to understand the more Sanskritised form of Hindi.
Colloquial Hindi is mutually intelligible with another register of Hindi-Urdu called (Modern Standard) Urdu. Mutual intelligibility decreases in literary and specialized contexts which rely on educated vocabulary. The number of native speakers of Standard Hindi is unclear. According to the 2001 Indian census, 258 million people in India reported their native language to be "Hindi". However, this includes large numbers of speakers of Hindi languages other than Standard Hindi; as of 2009, the best figure Ethnologue could find for Khariboli dialect (the basis of Hindustani) was a 1991 citation of 180 million. This places Hindi in a three-way tie with Bengali and Portuguese for the fifth-largest language in the world.