Note part included European language (6)
I believe the answer is:
creole
'language' is the definition.
(creole is a kind of language)
'note part included european' is the wordplay.
'note' becomes 'c' (musical note).
'part' becomes 'role' (eg a theatrical role).
'included' is an insertion indicator.
'european' becomes 'E' (abbreviation e.g. EU).
'role' going around 'e' is 'reole'.
'c'+'reole'='CREOLE'
(Other definitions for creole that I've seen before include "Descendant of French settlers as in New Orleans" , "Aerials (E, not S)" , "White descendant of French ancestors as in New Orleans" , "Person of mixed descent" , "Language mixture" .)