Punjab
The major language spoken in the Punjab is Punjabi. In the Indian Punjab this is written in the Gurmukhi script. Pakistan uses the Shahmukhi script, that is closer to Urdu script. Hindi, written in the Devanagri script, is used widely in the Indian states of Himanchal Pradesh and Haryana. Several dialects of Punjabi are spoken in the different regions. The Majhi dialect is considered to be textbook Punjabi and is shared by both countries.
Demographics of Pakistan
On the annexation of Sindh (1843) and Punjab (1849), the British Raj encouraged its use as the "lingua franca" and subsequently banned the use of Persian, which had been the "lingua franca" of the region for many centuries before. Persian had been introduced by Central Asian Turkic invaders who migrated into South Asia, and had been patronised by the Turko-Afghan Delhi Sultanate. This language change was designed to institute a universal language throughout the then British Raj in South Asia as well as minimize the influence that Persia, the Ottoman Empire and Afghanistan had on this transitional region.