At independence, Pakistan established a highly Persianized literary form of Urdu as its national language.
Because of the difficulty in distinguishing between Urdu and Hindi speakers in India and Pakistan, as well as estimating the number of people for whom Urdu is a second language, the estimated number of speakers is uncertain and controversial.
Owing to interaction with other languages, Urdu has become localized wherever it is spoken, including in Pakistan itself.
Urdu and Turkish borrowed from Arabic and Persian, hence the similarity in pronunciation of many Urdu and Turkish words.
Arabic influence in the region began with the late first-millennium Arab invasion of India in the 7th century.
The communal nature of the language lasted until it replaced Persian as the official language in 1837 and was made co-official, along with English.
Urdu was promoted in British India by British policies to counter the previous emphasis on Persian.
Urdu words originating from Chagatai and Arabic were borrowed through Persian and hence are Persianized versions of the original words.
For instance, the Arabic ta' marbuta ( Nevertheless, contrary to popular belief, Urdu did not borrow from the Turkish language, but from Chagatai.
English has exerted a heavy influence on both as a co-official language.
There are over 100 million native speakers of Urdu in India (more than 80% of it) and Pakistan together: there were 52 million and 80.5 million Urdu speakers in India some 5% and 6.5% of the total population of India as per the 20 censuses respectively; However, a knowledge of Urdu allows one to speak with far more people than that, because Hindustani, of which Urdu is one variety, is the fourth most commonly spoken language in the world, after Mandarin, English, and Spanish.
Thus linguists usually count them as one single language and contend that they are considered as two different languages for socio-political reasons.