Yakety-yak (7)
I believe the answer is:
chatter
'yakety-yak' is the definition.
(I know that yakety-yak can be written as chatter)
This is the entire clue.
(Other definitions for chatter that I've seen before include "Talk incessantly" , "Rabbit on" , "Idle talk" , "Talk noisily" , "Small talk" .)