Anyway, the point is that this is brilliant. Just think of the practical applications! If there's a better way to make your students focus on word choice and sentence structure, I don't know what it is.
Plus, it frees up all kinds of time for you, as an instructor. Your students concentrate wholly on a tiny thing for a really long time; you do what you want. Also, I totally already planned this lesson for you, so you don't have to work this weekend.
If my high school history teacher had known about this technique, then I feel certain that we all would have been pretending to be crusading children at 1% speed for a whole year instead of watching movies about the lives of the saints.