When the Muslims came to India, they gradually adopted the local languages. Many of their kings and military and religious leaders in the Northern, Southern, Eastern and Western India acquired literary distinction in their regional languages. Tipu Sultan of Mysore and Abdullah Qutub Shah of Golcanda were reputed poets. The Muslims spoke local languages, wrote in local languages and composed poetry in local languages, but it was not, and could not be, a one-way traffic. Their own language, i.e. Persian, also influenced the local languages. This is a natural process; language does not remain static: if it did, it would die. Every living language absorbs foreign words foreign ideas, and thus its strength grows and its beauty is enhanced. Thus, the daily contact in social gatherings, markets and administration gave birth to a composite language, Urdu.
“Urdu” is a Turkish word. Some say, it means army; others say, it means market. Be it as it may. The implication is the same: When people mingled with each other, in army or in market, this new language came into being. There is a difference of opinion concerning its birth-place. A group claims it was born at Delhi while another one says it was at Hyderabad (Deccan) in the South. What is certain is that the new language appeared in both places almost simultaneously; and it shows that there was a widespread inter-action and give-and-take ranging from Delhi in the north to Hyderabad in the south.
Urdu was, and still is, the commonly spoken language in a vast area of India and Pakistan. The Hindi-Urdu conflict is a bitter legacy of post-World War I politics in India.  It may be said truthfully that as far as the spoken language is concerned there is little difference between Hindi and Urdu, The basic difference is in the scripts —the language written in Persian script is called Urdu, while that written in Devnagari script is Hindi. Of course when it comes to literary works, the Urdu writers and poets use many Arabic  and  Persian  words  and  phrases,  while  those  writing  in Hindi  lean  mostly on  Sanskrit  expressions. 

In  some cases  this tendency  leads  the  writer*  (who  perhaps  to  prove  their  high erudition) to use Persianised or Sanskritised expression, as to make the Urdu or Hindi quite unintelligible to the common masses. However, the Urdu language was a common bond among the people of India, and especially between Hindus and Muslims. It was Urdu that gave India its famous revolutionary slogan, Inqilab zindabad (long live the revolution) which was heard from Assam to North-West Frontier, and from Kashmir to Ras Kumari. It is still heard in political rallies and processions. Urdu was not confined to the Muslims; hundreds, even thousands, of its writers and poets were, and are, Hindu. Pandit Rattan Nath Sarshar, Munshi Prem Chand, Brij Narain Chakbast, Daya Shankar Nasim, Firaq Gorakhpuri, Sahir Lodhyanawi, Rajendra Singh Bedi, Jagannath Azad, Arsh Malsiyani, Tilok Chand Mahroom, Gopi Chand Narang, Molvi Mahesh Parshad are just a few names that have come to mind at random.
We may also say that the Urdu language, or more correctly the Islamic literature, was saved, preserved and put in the hands of the public by a famous Hindu publisher, Munshi Nawal Kishore of Lucknow. This great son of India opened his eyes during the reign of the East India Company, and lived to see India being ruled by Queen Victoria. He started a printing press, and unearthed rare books of Hindu and Islamic philosophies, religions and literatures in Urdu, Arabic, Persian, Hindi and Sanskrit, and got them printed. This Hindu was held in such a great esteem that when the Muslim king of Afghanistan visited India, he made special request to the viceroy of India to make arrangements so that he could meet Munshi Nawal Kishore.
Pandit Jawahar Lal Nehru, the first prime Minister of India spoke Urdu. Dr. Rajendraprasad, the first President of India, has written in his auto-biography that his education began not with “Shri Ganesh” (i. e.. the Hindu formula) but with ” Bis-millahi 'r-Rahmani 'r-Rahim' (i. e . the Muslim formula). He took Hindi as a subject in his B. A. class.
It was Urdu which was chosen when the first attempt was made by Indians during the British Raj to use an Indian language as the medium of instruction at the university level. When Mir 'Usman 'Ali Khan, the seventh Nizam and last ruler of Hyderabad state, established the Osmania University with this object in view, there were misgivings in many circles. But the attempt proved tremendously successful. Committees were formed to coin Urdu terms for scientific and other subjects. Men of repute in various fields of knowledge were engaged to write books for the courses of studies. And teaching in Urdu medium started up to the Masters courses. And this was done without sacrificing the high standards of education. Soon the Oxford University in Britain recognised its degrees.
Unfortunately, the bitterness after the partition of India prompted the Indian leaders to deprive Urdu of its rightful place in India. Osmania University was turned overnight into a Hindi University; and all the academic and literary work done there in Urdu was relegated to oblivion and none of those titles are now available. Although, the Indian Constitution counts the Urdu as one of the 14 regional languages of India, the language has not been recognised yet as the regional language of any state or region. So, on governmental and official level, Urdu does not exist in India.
Pakistan has made Urdu its official language, although it is not a language spoken in any district of Pakistan. Punjabis speak the Punjabi language, Sindhis speak the Sindhi, Baluchis speak the Baluchi and the Pushto is spoken in the NWFR. Yet the official language of Pakistan is Urdu. Although it has been banished from U.P., Delhi and Hyderabad, the places where it was born, but —so far as the public support is concerned— it still flourishes in those areas. The number of the magazines and newspapers published in Urdu surpasses that of every other official language except Hindi.