How are Hindi and Urdu historically related?

Hindi and Urdu are historically and linguistically deeply intertwined, sharing the same Indo-Aryan base and originating from the regional Apabhramsha of northwestern India.1

Developing in the 13th century around Delhi and Meerut, they emerged as a common lingua franca known as Hindustani, which facilitated interaction between local speakers and those using Persian, Arabic, and Turkic languages. For centuries, this speech was referred to by various names, including Hindvi and Hindi, before the term Urdu—literally "the language of the camp"—became prominent.21

While they remain mutually intelligible with nearly identical grammar and phonology, they are often treated as independent languages due to their distinct lexicons and writing systems. Urdu draws heavily from Persian and Arabic and is written in the Nastaliq script, whereas Hindi incorporates more Sanskrit vocabulary and uses the Devanagari script. This divergence was intensified by 19th-century standardization efforts and the political partition of the Indian subcontinent.132