Hi N.,
I used to teach in a PPI (pre-primary impaired) classroom in a school for kids with special needs in Michigan. Our school system evaluated babies from new born thru adult. After seeing so many kids pass through my door my advice to you would be to contact your school system and ask if he can be evaluated. Please ask them to provide you with the phone number for the director of specail education. Now don't let this freak you out. If there is a problem with speech it can be caught early which leads to, on most occassions, easy speech classes in a program. One might think that it is best to wait until school age, but with early intervention he will be on the fast track with needed learning. All parents are afraid to think that their baby/child has something wrong with them. Please don't be afraid; you will just be requesting testing. It will be much easier on you and he if began early before bad habits set in. What ever you do don't talk for him because it will make matters even worse. Confront the problem and know that there are many caring speech teaches out there to help you and him. You will learn from the experts on how to carry over the training at home. We had many parents who would rather coddle their little ones than fight for them and teach them at home too. If any school work doesn't carry over at home (where their kids are most of the time) most of the teaching just goes out the door.
Most pediatricians aren't aware of the help that is available through our schools. Plus this testing is free from a wide variety of experts. My daughter's doctor didn't and he totally mis-diagnosed her; just telling me it was ADD. I wish I had known about this help long before she began kindergarten! This is why I went into the field. You will feel much better just knowing what is wrong or not at all.
Be willing to fight for him! There have been many program cut backs since 9/11. Our government has chosen to put our tax dollars into the war on terrorism thus leaving our precious little ones put out to dry. Good luck and be strong for him always.