Looks great and I am your target customer prior language experience but very out of practice and wanting to go from adequacy to fluency), but why phone-only? I was quite disappointed as I have a Mac but don't own an iPhone, and while I'd be willing to pay for this I don't want to buy a new device just to try it out. Another reason is that for study I actually like to sit at a desk and make notes with a pencil on paper.