Urdu

What native north Indians speak  formally on streets is Urdu or Hindustani as Urdu was known once. Hindi, a renamed version of khadi  boli ( contrasting with more natural and older Awadhi, Bhojpuri etc) of 19th century primarily remained a spoken or rather a written language of official state communication only. Fifteen Crore Pakistanis speak Urdu either as first or second language. Most of the north India too speaks mix of Urdu and modern sanskritized Hindi in bazaars and streets though they may use  Devanagari script for writing. The syntactic usage from Urdu or Hindustani defines foundation of Hindi or Khadi Boli.  Urdu with whatever name it was known earlier had been official language of intercommunication for three centuries or more for large part of India. It had been a universal court and revenue language with rich vocabulary even during British times. Land records had been all in Urdu during English period too.  It acquired and built its large vocabulary from various Indian languages and also from Sanskrit, Arabic and Persian. Charlatans of communal bigotry have associated it with one religion only and created negative enigma around its script. Urdu script is not that difficult and can be mastered with much simpler learning curve. Its popularity and sustenance for centuries is proof of its ease of use. True worth and depth of any language can be measured from popularity of its poetry.  No one needs a proof for guessing popularity of Urdu gazals, sher and nazms. Urdu is without considering its usage of script is widest spoken language and has a legacy we should be equally proud as much as we love Tamil, Panjabi, Kannada, Telugu, Malayalam, Marathi, Bhojpuri or Bangali.