Preliminary speech in favour of record being heard (8)
I believe the answer is:
prologue
'preliminary speech' is the definition.
'prologue' can be an answer for 'speech' (I have seen 'Introductory speech ' mean 'prologue' so perhaps 'speech' could also mean 'prologue'). I'm unsure of the 'preliminary' bit.
'in favour of record being heard' is the wordplay.
'in favour of' becomes 'pro' (being pro a particular cause).
'record' becomes 'log' (log is a kind of record).
'being heard' becomes 'ue' (I am not sure about this - if you are sure you should believe this answer much more).
'pro'+'log'+'ue'='PROLOGUE'
Can you help me to learn more?
(Other definitions for prologue that I've seen before include "Introductory piece" , "opening speech" , "Introductory passage" , "Introductory scene" , "Introductory speech" .)