Are vocal expressions able to start to express language? (9)
I believe the answer is:
cantonese
'language?' is the definition.
(Cantonese is an example)
'are vocal expressions able to start' is the wordplay.
I cannot really see how this works, but
'are' could be 'a' (short for 'are', historical unit of measurement) and 'a' is found within the answer.
'to' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'to express' acts as a link.
(Other definitions for cantonese that I've seen before include "way to cook" , "Asian language?" , "Chinese language" , "such food?" , "Form of Chinese" .)