Fashioned himself a European language (7)
I believe the answer is:
flemish
'a european language' is the definition.
'fashioned himself' is the wordplay.
'fashioned' indicates an anagram.
'himself' anagrammed gives 'FLEMISH'.
(Other definitions for flemish that I've seen before include "tongue" , "Second official language of Belgium" , "Of Flanders, like its language" , "from the Low Countries" , "Belgian language" .)