Story young girl lisped (4)
I believe the answer is:
myth
'story' is the definition.
(myth is a kind of story)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for myth that I've seen before include "Tall tale" , "Fancy" , "Delusion" , "Fanciful story" , "Illusion" .)