my 3 yr old daughter has trouble saying what she wants ?

i have a 4 yr old who has a slight lisp with the letter s ,u can hear the s but u see her tongue sticking out but we r doing tongue therapy to help her ,
   my question is abt my 3 yr old daughter who also has a slight very light s lisp but what bothers me is that when she talks it takes her a long time to get what she wants to say ,example if she wants a cup of juice she will say
" IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII WWWWANT A CUP OF JUICE"  
  after getting the long 2 first words out shes ok ,,i stop her and say think what u wanna say b4 saying it ,at the moment she called her sister without any delay and then was like "YOUUUUUUUUUUUUUUUUU HAVE TO STAY"
i dont know if this is a problem ,im gonna speak to her doc abt it in her next appoinment but hought to ask and see if anyone knows anything abt this .and thank you .