I have a grade school-aged niece who will love this, but the clock is a little fast for the age group this game is targeted towards. With a little work on graphics and such, I can see this being used by parents for kids with trouble in English class.
I like the idea, although in my opinion, it could use a few improvements. Mainly the content I think has to me more direct/specific.
Now this is an excellent learning game for those who've gotten a bit into english already! Others consider me quite skilled in the english language for a non-english person, yet even I made a few mistakes here and there. Turns out that even someone of my apparent skill can get further using a game like this. And the story behind the game isn't too bad either.
It seems that you have a great skill for both creating a good game, AND for teaching! I give all my fivers to this. It deserves it!
The game has a tonne of potential but no eventual goal or direction is specified. There needs to be a better progression and development of goals and targets.