Why Write? Writing is one of the major forms by which people are able to communicate. But beyond the idea that it is just a way for people to communicate, there are people who would call themselves "writers." These writers may write for a variety of different reasons, but all of them share the common urge to write.
There are some who would say that they write only to share their ideas with the world. Others may do it to achieve some kind of catharsis, writing down their pain so they can move on with their life. And still there are other writers who write to organize and arrange the constant rumblings of their mind into something a normal person could understand. They translate their messy thoughts into (in this case) English and give them form, releasing the true meaning of them onto a sheet of paper.
Being one who falls into the category of the "messy thinker," I write to see my thoughts mastered and to have them reach their full potential, or at least to the best of my ability.
For many writers, the act of writing is the only way for them to truly show others who they are on the inside. They may be incapable of expressing themselves in any other form, and may also lack the talent of conversing well with others. These people need to take time to really listen to their mind and to come up with how they think and feel about something.
For these people, writing is an extremely important part of who they are and how they relate to others - it being their only source of genuine communication. It is through their writing that others can see a glimpse into the writer's mind.
Sadly, it seems all too likely that there are "writers" out there who lack the skills necessary to translate their mind onto a page. Whether it be due to an improper education or any number of possible circumstances. This is just one more reason for us to put more of a value on reading and writing, which unfortunately seems to be less important to people nowadays than it was just a few years ago.
Imagine having thoughts so numerous and fast moving that they are almost foreign to you. Imagine that you have no way of explaining to others, let alone yourself, what you truly think and feel about a subject.
I would assume that this is the reason for students who do not participate in class or for them not being able to answer a question. It is not that they do not know, it is just that they lack the means to share their knowledge properly with others. I know that this was, at the very least, part of the reason why I shied away from raising my hand throughout my school career.
So teach a child to read and write, and you teach them how to share the beauty of their mind with those around them.