Translation:Aamir is from Delhi so he speaks English.
If "इस" means this and "लिये" means for, it should be "this for"! Why is it "thats why"??
I think of it this way: इस = this, लिये = for, so इसलिये = for this (reason). Aamir is from Dehli, so (= for this reason) he speaks English.