Our third child, a boy two years, nine months, has, in comparison to his siblings, delayed speech development. He seems to have the physical ability to make the sounds, but has trouble stringing them together in sequence. He has developed a very effective "language" of his own and his comprehension of English is age-appropriate. He becomes frustrated quite quickly whenever I attempt to "play" word/language games with him. What would you recommend we do from here?
A mom's "gut feeling" about her child is very important, so there may be something here. Before we jump to conclusions, let's consider a couple of possible explanations. Since your son has older siblings, he may not have had to talk very much -- the others do it for him. This is often seen in families in which the older, more verbal brothers and sisters almost smother the little one with language, resulting in what appears to be a delay, but what really falls in the category of "no need to talk much." It could also be that your almost three year old is putting all his energy (and native talents) into nonverbal acts. Is he an athlete in training who possesses exceptional physical skills (balance and movement)? Also, children who are intellectually talented often do not use a lot of language for the first couple of years and then "talk like adults" once they start.
It's good that you have determined that your son has the physical ability to make sounds, and also that he is "inventing" a language that seems to have a structure of its own. It's also great news that he has good receptive language, or the ability to understand the language of others. However, since he has trouble stringing words together and because he's frustrated with language games, there may be an underlying expressive language problem. When he turns three, he's eligible for a speech and language evaluation from the public schools. Just call the early childhood director or the administrator of special education and make that request. Or, you can have this evaluation done privately at your expense (some insurance policies cover this service, especially with a referral from your pediatrician -- by the way, what does he/she say about this?). If you want a private evaluation, contact the speech and language department of your local hospital or ask your pediatrician for a referral to a speech and language pathologist (make sure that they have worked with lots of little kids).