How old is your child? Are you and your doctor concerned about articulation or language or both?
If your child is under 4 contact the Infant & Toddler program for Charles County Public Schools. I believe they should have a Childfind representative.
If over 4 but not in Kindergarten contact the Early Childhood department of Charles County Public Schools.
If older than Kindergarten, contact the child's school directly and request a PST (Pupil Services Team) meeting to discuss your concerns with your child's speech. You can ask your child's teacher to begin the process or ask the Guidance counselor or Assistant Principal or whoever is the IEP chairperson.
Good luck!
( I say all this because you and your child are entitled to FREE speech services if he qualifies based on their testing)
I think the OP should follow through with the referral with Children's, as well. Sometimes you get two different standards of testing. For example, the school system has a different standard vs. medical testing. Also, even though there are timelines in place once your child is identified with Child Find, it can be a long process before any services (if any) begin.
Children's has developmental doctors who can test your child and then refer you to appropriate services. You can take those test results to the school system as well. The school has to at least consider that testing, and then you can compare that with the testing they do to come up with an appropriate plan of therapy for your child. It can't hurt to cover all your bases. (I didn't have a lot of advice on the "in's and out's" of the system when I was going through this with my son 18 years ago- I wish I had known parents who could have helped me back then.)
My advice: follow through with Children's and the school system at the same time. (Child Find, etc.)