Speech Therapy

So my oldest son who is 7 years old can't say his R's. This has been an issue since he could talk, but his
Pediatrician kept saying he would grow out of it....keep waiting. We waited for 5 years. It didn't get better, so finally after some begging we are able to start speech, X loves it, can't get enough of it, he is so excited to start being able to say words right.