Talk to a soft toy (7)
I believe the answer is:
prattle
'talk' is the definition.
(I know that prattle is a more specific form of the action talk)
'soft toy' is the wordplay.
'soft' becomes 'p' (musical abbreviation for piano, 'soft').
'toy' becomes 'rattle' (I've seen this before).
'p'+'rattle'='PRATTLE'
'to a' is the link.
(Other definitions for prattle that I've seen before include "Inconsequential chatter" , "Be vapidly garrulous" , "Childish talk" , "Talk emptily" , "Talk childishly" .)