Games are excellent teaching tools. After all, what are they if not mechanisms that teach us how to use themselves through interaction? By playing, we learn how to play. It's something of a no-brainer that those same loops of feedback and reinforcement can be used for more than training us to be really good at headshots.
Here to illustrate the point is Hiragana Pixel Party, one of many apps that promise to teach you Japanese. The difference here is that it's a rhythm-action game, and the only way to get good is to understand Japanese writing. You play because you want to win; you want to earn all three ranks for every stage. Language acquisition is just the mechanism you engage with to achieve your goal.
Our hero is the aptly named Hiro, who jogs his Limbo-esque silhouette across the screen to the sound of jaunty chip-tunes. Up pops a young girl, who starts by uttering vowel sounds in time with the music. You then copy her, by tapping on the relevant symbols, helping Hiro hop over obstacles in the process. The more obstacles he clears, the more birds he attracts. Make a mistake and one of the birds flies away. Run out of birds and Hiro's adventure in linguistics is over.