West Punjab
At Independence there was a Muslim majority in West Punjab with significant Hindu and Sikh minority. Nearly all of these minorities left West Punjab for India, to be replaced by large numbers of Muslims fleeing from the opposite direction. The official language of West Punjab was Urdu but most of the population spoke Punjabi using the Shahmukhi script. The linguist George Abraham Grierson in his multi volume Linguistic Survey of India (1904–1928) considered the various dialects up to then called "Western Punjabi", spoken in North, West, and South of Lahore in what is now Pakistani Punjab, as constituting instead a distinct language from Punjabi. (The local dialect of Lahore is the Majhi dialect of Punjabi, which has long been the basis of standard literary Punjabi.) Grierson proposed to name this putative language "Lahnda", and he dubbed as "Southern Lahnda" the coherent dialect cluster now known as Saraiki spoken in Multan Dera Ghazi Khan and Bahawalpur division and "North Lahnda" now known as Potwari spoken in Rawalpindi division and "Western Lahnda" now known as Hindko spoken in the regions bordering Khyber-Pakhtunkhwa.
Languages of Pakistan
Bengali (بنگالی) is not an official language in Pakistan, but a significant number of Pakistani citizens have migrated from East Bengal and live in West Pakistan or East Pakistan prior to 1971. Bengali was recognised as the second official language of Pakistan on 29 February 1956, and article 214(1) of the constitution of Pakistan was reworded to "The state language of Pakistan shall be Urdu and Bengali". Others include illegal immigrants who migrated from Bangladesh after 1971. Most Pakistani Bengalis, are bilingual speaking both Urdu and Bengali, and are mainly settled in Karachi.