Talk may be firm, and otherwise never about son (8)
I believe the answer is:
converse
'talk' is the definition.
(conversing is a kind of talking)
'firm and otherwise never about son' is the wordplay.
'firm' becomes 'co' (a firm is a company).
'and' is a charade indicator (letters next to each other).
'otherwise' indicates anagramming the letters.
'about' says to put letters next to each other.
'son' becomes 's'.
'never' after 's' is 'snever'.
'snever' with letters rearranged gives 'nverse'.
'co'+'nverse'='CONVERSE'
'may be' acts as a link.
(Other definitions for converse that I've seen before include "Remain silent? No" , "Talk - opposite" , "discuss" , "speak" , "Quite the opposite!" .)