Speaks of old scales (6)
I believe the answer is:
orates
'speaks' is the definition.
(orating is a kind of speaking)
'old scales' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'scales' becomes 'rates' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'o'+'rates'='ORATES'
'of' is the link.
Can you help me to learn more?
(Other definitions for orates that I've seen before include "Talks pompously" , "Speechifies" , "Makes lengthy or pompous speech" , "Talks grandly from a platform" , "Speaks formally, makes speech" .)