Wind up speaking in a foreign language (7)
I believe the answer is:
finnish
'a foreign language' is the definition.
(I've seen this before)
'wind up speaking' is the wordplay.
'wind up' becomes 'finish' (synonyms).
'speaking' indicates a 'sounds like' (homophone) clue.
'finish' is a homophone of 'FINNISH'.
'in' acts as a link.
(Other definitions for finnish that I've seen before include "Nationality of citizens of Helsinki" , "foreign language" , "Eg, native to Helsinki" , "European language" , "race" .)