Mentions further that many are in sad disarray (4)
I believe the answer is:
adds
'mentions further' is the definition.
The definition and answer can be both to do with communicating as well as being verbs in their -s form.
Perhaps you can see a link between them that I can't see?
'many are in sad disarray' is the wordplay.
'many' becomes 'd'.
'are in' is an insertion indicator.
'disarray' indicates an anagram.
'sad' is an anagram of 'ads'.
'd' inserted into 'ads' is 'ADDS'.
'that' is the link.
Can you help me to learn more?
(Other definitions for adds that I've seen before include "Puts (numbers) together" , "Finds the sum (4)," , "Counts" , "Contributes further" , "Appends or increases" .)