Listen twice for approval from audience (4,4)
I believe the answer is:
hear hear
'approval from audience' is the definition.
'hear hear' can be an answer for 'approval' (I have seen 'express approval' mean 'hear hear' so perhaps 'approval' could also mean 'hear hear'). I am not certain of the 'from audience' bit.
'listen twice' is the wordplay.
'listen' becomes 'hear' (I've seen this before).
'twice' indicates the doubling of some letters.
'hear' doubled is 'HEAR HEAR'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for hear hear that I've seen before include "express approval" , "Agreed" , "Listen, listen - it's approval" , "Jolly good!" , "Well said!" .)