In a manner of speaking, raise doubts these are wordy reference books (12)
I believe the answer is:
dictionaries
'wordy reference books' is the definition.
'dictionaries' can be an answer for 'books' (dictionary is a kind of book). I am not sure about the 'wordy reference' bit.
'in a manner of speaking raise doubts these are' is the wordplay.
'in' means one lot of letters goes inside another.
'a manner of speaking' becomes 'diction' (a person's way of speaking).
'raise' says the letters should be written backwards.
'doubts' becomes 'seir' (I can't justify this - if you can you should believe this answer much more).
'these are' becomes 'a' (short for 'are', historical unit of measurement).
'seir' reversed gives 'ries'.
'diction'+'ries'='dictionries'
'dictionries' enclosing 'a' is 'DICTIONARIES'.
Can you help me to learn more?
(Other definitions for dictionaries that I've seen before include "reference books" , "works of reference" .)