Judge again concerned with morons' start of sentences (8)
I believe the answer is:
reassess
'judge again' is the definition.
('assess' is an answer for 'judge' so perhaps 'reassess' is OK for 'judge again')
'concerned with morons' start of sentences' is the wordplay.
'concerned with' becomes 're' (re can mean regarding, concerning).
'morons'' becomes 'asses' (I am not sure about this - if you are sure you should believe this answer much more).
'start of' suggests taking the first letters.
The initial letter of 'sentences' is 's'.
're'+'asses'+'s'='REASSESS'
Can you help me to learn more?
(Other definitions for reassess that I've seen before include "reconsider" , "Newly evaluate" , "Have second thoughts" , "Make another appraisal" , "Re-evaluate" .)