Talk further about relationship (7)
I believe the answer is:
oration
'talk' is the definition.
(an oration is a speech)
'further about relationship' is the wordplay.
'further' becomes 'on' (synonyms).
'about' indicates putting letters inside.
'relationship' becomes 'ratio' (relationship between two numbers).
'on' placed around 'ratio' is 'ORATION'.
(Other definitions for oration that I've seen before include "Power of speech" , "words" , "Platform speech" , "A long ceremonial speech" , "eulogy" .)