Longcut, we are in the same position with our DS17. And you're right, it has become an issue now that he has to write not only English essays, but even science lab write-ups, when it comes to the "observations" part. I believe it is due to anxiety, but he is being evaluated, as well. Yesterday he described in delighted detail for 20 minutes the cool national lab they visited on a field trip, but "what do you want for dessert?" He couldn't answer. I used to rephrase questions as you do, but the world doesn't do that for them, and I wish I'd realized sooner that it is an issue.
