Speech impediment? (7)
'speech impediment' is the definition.
(I know that lisp is a type of dyslalia)
This is all the clue.
(Other definitions for lisp that I've seen before include "Have difficulty pronouncing `s'" , "Be unable to pronounce S" , "Slip into speech defect" , "Speak with defective sibilants" , "speak imperfectly" .)
'impediment?' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'speech' is the wordplay.
I cannot quite see how this works, but
'speech' could be 'heck' (heck is a kind of speech) and 'heck' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for heckler that I've seen before include "One interrupting speech" , "Political barracker" , "Person who jeers speaker from the crowd" , "One interrupts a public speaker with abusive comments" , "Unruly audience member" .)