Language modulations adopted by staff (9)
I believe the answer is:
cantonese
'language' is the definition.
(Cantonese is an example)
'modulations adopted by staff' is the wordplay.
'modulations' becomes 'tones' (I can't explain this - if you can you should believe this answer much more).
'adopted by' means one lot of letters goes inside another (I've seen this in other clues).
'staff' becomes 'cane' (I've seen this before).
'tones' going within 'cane' is 'CANTONESE'.
Can you help me to learn more?
(Other definitions for cantonese that I've seen before include "Eastern language" , "Chinese language" , "Form of Chinese" , "way to cook" , "Asian language?" .)