Solid, but not to be used as a stand-alone learning game.
In order to proceed through the game, you must master words that are given by playing random games. Most of these games aren't helpful at all. The only worthwhile games are Flash Cards, Multiple Choice, and Write Cards. Although you can just play the games, master the words, and move on, it's better if you have a notebook or two to study with.
This game is pretty decent, but you should still use two or three internet sources along with it if you want to actually learn something.