Ten operas rewritten in international language (9)
I believe the answer is:
esperanto
'international language' is the definition.
(I've seen this before)
'ten operas rewritten' is the wordplay.
'rewritten' is an anagram indicator.
'ten'+'operas'='tenoperas'
'tenoperas' is an anagram of 'ESPERANTO'.
'in' acts as a link.
(Other definitions for esperanto that I've seen before include "contrived language" , "Language invented by Dr Zamenhof" , "Universal language" , "Artificial speech-form" , "artificial tongue" .)