European language buff (6)
I believe the answer is:
polish
This clue is a triple definition!
'european' is the first definition.
(I've seen this before)
'language' is the second definition.
(Polish is an example)
'buff' is the third definition.
(I've seen this before)
(Other definitions for polish that I've seen before include "Buff up - foreign language" , "Shine with soft cloth, say silverware" , "make things shiny" , "tongue" , "Make smooth and glossy" .)