We are proud speaking in our mother tongues as well, but almost Pakistanis are very fluent in our national language as well, which holds great pride for us. For example: as a Bihari, I speak Bhojpuri with my parents & grandparents, & speak Urdu with the rest of the Pakistani people I know with great pride. Punjabis will speak in Punjabi with one another, Balochis will speak Balochi/Persian with each other, Pakhtuns will speak Paktho with each other, Sindhis will speak in Sindhi with one another, Gujaratis will speak in Gujarati with one another, people from Chitral speak in Chitrali with one another, as well as many other languages. Pakistan is very diverse as well in many ways my friend. However, when different ethnic groups speak to each other, we are fluent enough to communicate with each other in Urdu, & take great pride in using Urdu with one another. Urdu is a great source of pride for all of us, & almost all Pakistanis are very fluent at speaking it.
When Indians go to Western countries, they are divided amongst each other, in terms of Gujaratis, Maharashtrians, Punjabis, Southies etc. Every Pakistani calls themselves "Pakistanis" in the West, no one refers to themselves in terms of their ethnic groups. Indians belonging from different states have problems in communicating with one another if they are poor in both Hindi & English, & this is the case found with Indians that come from smaller cities in India.