Worker and speaker taking exercise (8)
I believe the answer is:
operator
'worker' is the definition.
(I know that operator is a type of worker)
'speaker taking exercise' is the wordplay.
'speaker' becomes 'orator' (orator is a kind of speaker).
'taking' is an insertion indicator.
'exercise' becomes 'pe' (Physical Education).
'orator' going around 'pe' is 'OPERATOR'.
'and' is the link.
(Other definitions for operator that I've seen before include "Wheeler-dealer - telephonist" , "Switchboard employee" , "User of machinery" , "Mathematical symbol" , "User of machine etc" .)