Hindi

Hindi is a standardised and sanskritised register of the Hindustani language (Hindi-Urdu) that is associated with the Hindu religion.

Hindustani is the native language of people living in Delhi, Haryana, Western Uttar Pradesh, Bihar, northeastern Madhya Pradesh, and parts of eastern Rajasthan, and Hindi is one of the official languages of India.

Colloquial Hindi is mutually intelligible with another register of Hindustani, (Modern Standard) Urdu, which is associated with the Muslim religion. The two varieties of Hindustani are nearly identical in basic structure and grammar, and at a colloquial level also in vocabulary and phonology. Mutual intelligibility decreases in literary and specialized contexts, which rely on educated vocabulary drawn from different sources.

People who identify as native speakers of Hindi are not just those speakers of Hindustani who are Hindu, but also many speakers of related languages who consider their speech to be a dialect of Hindi. In the 2001 Indian census, 258 million people in India reported Hindi to be their native language; as of 2009, the best figure Ethnologue could find for speakers of actual Hindustani Hindi (effectively Khariboli dialect less Urdu) was a 1991 figure of 180 million This makes Hindi approximately the sixth-largest language in the world.

Source: Wikipedia