Native speakers of Urdu are spread across South Asia. The vast majority of them are Muslims of the Hindi–Urdu Belt of northern India, followed by the Deccani people of the Deccan plateau in south-central India (who speak Deccani Urdu), the Muhajir people of Pakistan, Muslims in the Terai of Nepal, and the Biharis and Dhakaiyas of Old Dhaka in Bangladesh. The historical centres of Urdu speakers include Delhi and Lucknow, as well as the Deccan, and in the modern era, Karachi. Another defunct variety of the language was historically spoken in Lahore for centuries before the name "Urdu" first began to appear. However, little is known about this defunct Lahori variety as it has not been spoken for centuries.
The term "Urdu-speakers" does not encompass culturally non-native speakers who may use Urdu as a first or second language, which would additionally account for a much larger number of total speakers in South Asia.
History
From the early Muslim kingdoms developed Indian Muslim clan-groups who were well-rooted social groups that acted as warrior lineages providing court officers and military soldiers. These evolving communities or tribes played a key role in providing a local Muslim leadership.
Mughal Empire
As early as 1689, Europeans used the label "Moors dialect", which simply meant "Muslim", to describe Urdu, the language associated with the Muslims in North India, such as John Ovington, who visited India during the reign of Mughal emperor Aurangzeb:
The language of the Moors is different from that of the ancient original inhabitants of India, but is oblig'd to these Gentiles for its characters. For though the Moors dialect is peculiar to themselves, yet it is destitute of Letters to express it; and therefore in all their Writings in their Mother Tongue, they borrow their letters from the Heathens, or from the Persians, or other Nations.
Fall of the Mughal Empire
The rural Upper Doab and Rohilkhand was dominated by a literate and homogenous elite, who embraced a distinctive Indo-Persian style of culture. This service gentry, performing both clerical and military service for the Mughal empire and its successor states, provided cultural and literary patronage that contninued, even after the political decilne, to act as preservers of Indo-Persian traditions and values.
The end of Muslim rule saw a large number of unemployed Indian Muslim horsemen, who were employed in the army of the East India Company. Thus 75% of the cavalry branch of the British army was composed of a social group referred to as the "Hindustani Mahomedans". This included Indian Muslim Baradaris of the Urdu-Hindustani Belt such as the Ranghar(Rajput Muslims), Sheikhs, Sayyids, Mughals, and Indianized Pathans. British officers such as Skinner, Gardner and Hearsay had become leaders of irregular cavalry that preserved the traditions of Mughal cavalry, which had a political purpose because it absorbed pockets of cavalrymen who might otherwise become disaffected plunderers. The Governor-general insisted that it was incumbent upon the British to "give military employment" to various north Indian Muslim soldiers, particularly those "formerly engaged in military service of the Native powers". The lingua franca spoken in the army was a form of Urdu referred to in colonial usage as "military Hindustani".
The Indian Rebellion of 1857 was initiated by the 3rd Bengal Light Cavalry in Meerut, which was composed mainly of Indian Muslims. The mutineers made for Delhi, where its garrison revolted, massacring its British population, and installed Bahadur Shah Zafar as its nominal leader. The spread of the word that the British had been expelled from Delhi, interpreted as the breakdown of British authority, acted as a catalyst for mutiny as well as revolt. Regiments in other parts of northern India only revolted after Delhi had fallen. British characterizations of Muslims as fanatics took the fore during and after the Great Rebellion, as well as produced the Indian Muslims as a unified, cogent group, who were easily agitated, aggressive, and inherently disloyal.