Although Pakistani Punjabis do have a linguistic identity, their language identity takes a back seat to their religious identity. The reverse is the case with Bengalis in South Asia. Cases in point are Bangladesh and West Bengal in India. Before Bangladesh became an independent nation in 1971, it was part of Pakistan (called East Pakistan). Although Islamic identity was the main reason that Bangladesh became a part of Pakistan rather than India in 1947, the imposition of Urdu, the national language of Pakistan, on Bengalis was a major factor in the split between Pakistan and Bangladesh.
In contrast, Punjabi Muslims’ identity with their language is weaker than Bengalis’s identification with theirs. Therefore, although Punjabi speakers form a majority in Pakitsan (60%), the imposition of Urdu on Punjabis did not lead to a separatist movement as it did in the case of former East Punjab. The stance of Punjabi Muslims is to divorce themselves consciously from Punjabi in order to assert their national and religious identity.
— Tej K. Bhatia, Language in South Asia.