Hindi is one of the top first languages in the world. With around 425 million native and about 120 million second-language speakers, it ranks fourth after Mandarin, Spanish, and English. It's an Indo-Aryan language that's native to India, and according to the Indian Constitution, Hindi in Devanagari script is the Union's official language along with English.
Versions of Hindi are also spoken outside of India, though many of them derive from Bhojpuri, Awadhi, and other dialects. Hindi and Urdu are closely related languages, so speakers of either language can readily understand each other. Written Hindi, accomplished in the Devanagari script, carries strong Sanskrit influences.