So I want a AI that reads.

What are all of the methods that this can be done?

How can I make the AI understand a sentence and be lenient about spelling?

Also where can I find a open source dictionary and open source spell checker, if I need to fall back to comparing strings?

I really hope you have some ideas to share, otherwise this is going to be a long project.

The field that deals with this type of problem is natural language processing. It is a large and difficult field in which I am not an expert, but even an expert wouldn't be able to give you an introduction to the field in a forum post. See what you can learn now that you have the key words to search for.

Thanks Álvaro for leading me in the right direction.