Hi Kathe,
I am quite familiar with apraxia. My son didn't have that, he had global dysphasia, which means that he could not process language either coming into his brain or going out. Most people only have one or the other (expressive or receptive) but he was born with both. It is also very unusual to be born with both. (You can read a story about him here:
Of mitzvahs and miracles).
Usually this is a disorder that happens after a stroke, which is why his language pathologist concluded he may have had a stroke in utero.
Anyway, what I wanted you to know: first, you are not alone. If you haven't already, see if you can find a support group, because you learn so much from other people.
Second, I am assuming you are already hooked up with a good language therapist. The most important advice I can give you, and this is directly from our therapist, because we are still friends, and she tells me this is her biggest frustration: Do the homework with him. Every single day. No excuses. We found ways to do homework no matter where we were. I can remember being on line at Disney World. My dad had Jeff in his arms, I was behind them, and I was quizzing him: Name ten farm animals. Name ten things you'd find in a medicine cabinet. Name ten things in the kitchen.
It was grueling, especially when he had no comprehension at all. Your son probably has the comprehension, but lacks the ability to express it.
Children's brains are like plastic, and they keep reshaping as the child learns. You are lucky that he was diagnosed early and you have the opportunity to help him.
Let me tell you about my son. GB can vouch for me. He graduated from college with a bachelor in fine arts. He works for Apple, Inc. teaching other people how to use their computers and software. He never shuts up. He is brilliant, has a loving girlfriend, lives on his own, drives, makes his own decisions, and if you didn't know... you wouldn't know.
Yes, he had other learning issues, as most LD kids do. And occasionally, if he's tired, his language may sound a little bizarre. But not enough to make you go "huh?"
Hang in there. You are the most important member of your child study team.