Shown how wrong pronunciation may be (6)
I believe the answer is:
taught
'shown' is the definition.
(shown how to do something)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for taught that I've seen before include "given a lesson" , "Was coach" , "Imparted skills or knowledge to" , "Gave instruction" , "Educated" .)