Suggest it's dull speaking about work (7)
I believe the answer is:
propose
'suggest' is the definition.
(as in proposing a plan)
'dull speaking about work' is the wordplay.
'dull speaking' becomes 'prose' (I can't justify this - if you can you should give a lot more credence to this answer).
'about' indicates putting letters inside.
'work' becomes 'op' (abbreviation for opus).
'prose' enclosing 'op' is 'PROPOSE'.
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for propose that I've seen before include "Make an offer of marriage" , "Put forward for consideration" , "Put forward (motion)" , "Request" , "Offer for consideration" .)