In part an actor always has spoken (4)
I believe the answer is:
oral
'spoken' is the definition.
(similar in meaning)
'in part an actor always has' is the wordplay.
'in part' indicates a hidden word.
'ORAL' is hidden in the letters of 'actor always has'.
(Other definitions for oral that I've seen before include "Vocal test" , "Related to the mouth" , "Using speech rather than writing" , "Said - form of test" , "Viva voce" .)