I have been where you are. There is no danger in stygmatizing your son, as someone said, but there is danger in not getting someting identified out of fear of what it is. Stygma is in the eyes of those who are uniformed about developmental issues, and arises out of fear. Do not fear. He will be the same little boy if you help him as he was before you did, and you can help him. I can think of nothing worse than to delay or avoid intervetnion or identification out of the fear of being stygmatized by those around him, because failure to intervene will result in a much worse stygma than a terrific adult who once had speech therapy or more interventions that nobody knows about, which is quite likely. What you should beware of is anecdotal descriptions of kids who were just like your son, got no help, and are in gifted programs, are brain surgeons, rocket scietntists, etc...that may be true, but for every child who had a miracle, there are children like mine, who are miracles because they got the help they needed when they needed it, and that child and mine look just like yours does at this age. You would be taking a bet that your situation is not like mine, and the price is way to big if lose.
So, here is my suggestion. First thing, stop trying to identify things that he can do that will elimate a diagnosis. It does not work that way at all. There is not one particular thing that kids can do that will mean that they don't have a particular developmental delay, and you have enough red flags to go ahead with an evaluation with a Developmental Pediatrician without any qualification. That will take a long time too, so make the appointment now.
Call around to other speech therapists, and see if you can get him in sooner in the mean time, and start therapy for the speech issues that you see, and do not depend on the speech therapist to diagnose a global issue, many speech therapists can be very wrong about what they think the real issue is, and they are nto qualified to diagnose anything other than a speech issue.
Call ECI in your state, and get an appointment with them. You can locate the early childhood intervention program by calling your county's board of Developmental Disablities, they will know who to contact and what your state calls this program. They will come to you, and evaluate him, and provide therapy if he needs it free of charge. Do not depend on them to diagnose him or to provide all the therapy he needs. They are there to help him be functional, and you want more than that. When he turns three, contact your school district, and continue with state services through them, but again, always suplement with as much private service as you can afford. Both of these are federally funded state run programs in every state, and you can learn about advocacy for these programs at www.wrightslaw.com. Once he gets into the school district program, it is important that you learn to advocate.
You are not alone by any means. The biggest lesson is, never wait on develpment, and get as much intervention as you can, as early as you can. Know that even if you get a diagnosis, it may change, because development is a moving target, so be flexible, and continue to focus on intervention for the issues you see, and not what to call his condition. Learn about all his evaluation data from the wrightslaw site, you will be much better prepared if you understand how to read and interpret the data. And, keep your chin up. There was nothing you did to cause this, it happens. Stay on the standard path, it is not flashy, but it does produce results, you will likely hear about food and supplement or detox related "cures" and they are a waste of your time. Be healthy, and go forward with standard care.
M.
It is a myth that boys have slower development than girls. The developmental milestones are the same for both genders, and waiting on an evaluation because of this thought could be devistating to any child.