Language exercises adopted by new senator (9)
I believe the answer is:
esperanto
'language' is the definition.
(Esperanto is an example)
'exercises adopted by new senator' is the wordplay.
'exercises' becomes 'pe'.
'adopted by' is an insertion indicator (I've seen this in other clues).
'new' is an anagram indicator.
'senator' with letters rearranged gives 'esranto'.
'pe' going within 'esranto' is 'ESPERANTO'.
(Other definitions for esperanto that I've seen before include "Universal language" , "Personate (anag.)" , "Artificial speech-form" , "Artificial international language devised in 1887" , "largely unknown language" .)