Speech therapist's concern (4)
I believe the answer is:
lisp
'speech therapist's concern' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lisp that I've seen before include "Have difficulty pronouncing `s'" , "Slip into speech defect" , "Non-standard pronunciation" , "Slight speech impediment" , "Be unable to pronounce S" .)