Language spoken in Islamabad (4)
I believe the answer is:
urdu
'language spoken in islamabad' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for urdu that I've seen before include "Analyse and develop (an idea) in detail" , "Asian language written in Arabic script" , "Sanskrit language" , "Form of Hindustani" , "Language closely related to Hindi" .)