L.D.
Sounds like he may have an oral motor planning issue. Ask your pediatrician give you a referral to a speech therapist and occupational therapist to have him evaluated. You can also contact your State's early intervention service department and request and evaluation. They will come out to your home to do the evaluation and provide services to your son at home, free of cost. Sometimes the early intervention service department are overloaded and underfunded so, if you can get a private ST eval and treatment, I would definitely get on that as soon as possible while waiting for the state's services to begin.