The name of the Pakistani language with 4 letters is URDU.

Urdu developed in the 12th century AD and was a mixture of local language, Arabic, Persian, and Turkish.

This language is predominantly spoken in Eastern Pakistan. This language is spoken also in parts of India. Urdu is a fascinating language that I am trying to learn. I have ordered an Urdu course on Udemy and I am trying to speak conversational Urdu with some online friends.

For what its worth, to the English speaker, Urdu sounds like Arabic.

Check out my other post about Pakistan here.