Language spoken in old city of the French (4)

I believe the answer is:
urdu
'language' is the definition.
(Urdu is an example)
'city of the french' is the wordplay.
'city' becomes 'Ur' (ancient Sumerian city state).
'of the french' becomes 'du' ('of the' in French).
'ur'+'du'='URDU'
'spoken in old' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for urdu that I've seen before include "Foreign language" , "Sub-continental language" , "Language spoken by Moslems in Pakistan and India" , "Asian language written in Arabic script" , "Language closely related to Hindi" .)
