I came across a really good article on ideas.ted.com regarding introverted children in the classroom. My own daughter is definitely an introvert, and I know she struggles with things like participating in class, and even with the class environment itself. The article discusses how typical schools are really geared towards extroverts, and ways in which schools could adapt to the fact that 1/3 of the population are actually introverted.
Here's a section from the article, but I would encourage you to read the whole thing...I think we all can benefit - educators especially and even parents of extroverts.
"I’d like to challenge teachers to rethink what they mean by class participation and start thinking of it as classroom engagement instead. Participation ends up rewarding quantity, so you get kids raising their hands for the sake of talking, and that’s not really in anybody’s interest. But engagement recognizes that there are a lot of different ways to engage with the material and with your peers. If you think more broadly about it, a student who’s a good listener or who gives one really great, reflective comment is just as valued as the one who’s always raising their hand."
The full article can be found here: http://ideas.ted.com/how-to-teach-a-young-introvert/?utm_campaign=social&utm_medium=referral&utm_source=facebook.com&utm_content=ideas-blog&utm_term=education