Language using few words needs no introduction (4)
I believe the answer is:
erse
'language' is the definition.
(historical term for Scottish Gaelic)
'using few words needs no introduction' is the wordplay.
'using few words' becomes 'terse' (terse means brief or curt).
'needs no introduction' means to remove the first letter.
'terse' with its initial letter taken off is 'ERSE'.
(Other definitions for erse that I've seen before include "Possibly the language" , "Old Scots or Irish Gaelic" , "Irish Gaelic language" , "Kind of Gaelic for seer" , "Old name for Celtic languages" .)