I'm basically a shy person. In class, I like to sit in the back and observe. I grew up thinking I had a stupid sign on my forehead and haven't totally gotten over it. Participation in class has been something I tried to avoid.
I thought of this today during tai chi. My picture is on Wikipedia with the article on uncoordination. Not only do I have zero skills working my feet and my arms, I can't work them together and to make things worse, I can't even remember the steps. I try to hide in the back. Don't get me wrong, I love the class and the teacher and am actively trying to do the right thing for the entire class but I don't like to be on display and cringe if I have to demonstrate anything.
When I taught at Packemin, a big part of classroom observations involved getting every student to speak at least once. If you didn't do that, the person observing was not happy with the way the class was running. I knew there were always kids around kids like me who were happier blending into the background and were extremely uncomfortable having to speak or go to the board. That did not mean they weren't participating or learning. They just did these activities in their own way. I understand the need to speak in a language class or an ESL class but other classes don't necessarily need this component.
Every student not speaking is not a cause to rate a teacher unsatisfactory. In fact, letting a child sit quietly might be a better idea if speaking causing he child anxiety. It is a shame that administrators don't want to know this. Again, it is a one size fits all education.