Lahore tongue (4)
I believe the answer is:
urdu
'lahore tongue' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for urdu that I've seen before include "Indian language" , "An official language of Pakistan related to Hindi" , "Form of Hindustani" , "Channel to north of Isle of Wight" , "Language akin to Hindi" .)