The whole concept gets tiring after awhile. This app is designed like a game, and you have to "buy" material with rewards after making too many mistakes, or actually pay money for it. The constant ads and prompts to interact with the "game", make the learning experience clunky and tiring, Free version. In addition, the app goes overboard trying to be inclusive, the lesson content seems to increase the focus on issues, to the point of appearing to have an agenda. Not for everybody.