Don’t start talk about baby's toy (6)
I believe the answer is:
rattle
'baby's toy' is the definition.
(I've seen this before)
'don't start talk' is the wordplay.
'don't start' means to remove the first letter.
'talk' becomes 'prattle' (prattling is a kind of talking).
'prattle' with its first letter taken away is 'RATTLE'.
'about' acts as a link.
(Other definitions for rattle that I've seen before include "Baby's toy; sound of loose part" , "Make nervous; child's toy" , "led to Tweedledum and Tweedledees quarrel?" , "Noisy baby's toy" , "cause nervousness" .)