No. It was recently revealed that even a much simpler problem, detecting genitals in on-line worlds, was so difficult that the world was shut down. It might be possible to detect certain words with speech recognition, but the teacher will just use different words. http://fusion.net/story/143218/lego-universe-had-a-huge-dong...

Twenty years ago we learned that even censoring specific bad words in online chat rooms is impossible. http://articles.baltimoresun.com/1995-12-02/features/1995336...