the answer to your question is....

1.why do an englishman speak english??
2. why do philipino's speak tagalog??
3. why do a spanish guy speak spanish?

They speak because they are comfortable speaking it. And so are the Pakistani's or for anyone that matter. Not that they do know any other languages.

I know many pakistani friends thou they speak URDU well they do speak English well too and at work!!

Honestly speaking....your question seems to be stupid! U should have not wasted 2 -3 minutes that you took to post this on QL. Should have smoked a Cigar..would have been better.

Good day Super Hero!!