Ten operas rewritten in artificial language (9)
I believe the answer is:
esperanto
'artificial language' is the definition.
(Esperanto is an example)
'ten operas rewritten' is the wordplay.
'rewritten' indicates an anagram.
'ten'+'operas'='tenoperas'
'tenoperas' anagrammed gives 'ESPERANTO'.
'in' is the link.
(Other definitions for esperanto that I've seen before include "No repeats of this artificial language, strangely" , "in which many could communicate?" , "largely unknown language" , "Ape tenors (anag.)" , "Linguistic invention" .)