That's a good idea. I met a salesclerk one who spoke English very fluently. I asked him for tips on learning English well, and he said that he learned a great deal from SecondLife. Since the operating system and chat is all in English, he was motivated to pick up the language and use it correctly to communicate with others and to experience the "flow" of the game optimally (see Csíkszentmihályi). Although his primary goal was the playing experience, he learned effectively and with a high level of motivation, genuine feedback/reinforcement, and collaboration/interaction through the SecondLife forum.