Exploiting for educational purposes the motivational possibilities of games has been a goal of teachers since Classical times.2 In our own day, the marriage of computers and games seems, if anything, likely to heighten the fascination humans feel for games. There are a number of reasons why this should be so, aside from the novelty of the machines. Computers are an always-patient, accurate partner to their human users; can play their games at varying speeds according to the wish of the designer and player; never forget or change rules; and will play as often and for as long as the human likes. In addition they can nowbe programmed to mimic intelligence; to repond to, and answer in, ordinary language; and altogether to offer a most satisfying illusion that one is playing with another human. Paradoxically, the satisfaction may come more from the knowledge that it is an illusion than from any possible belief that the illusion is reality. Computer games are especially clear illustrations of how the unique capabilities of computers can be used to create motivating environments, writes Thomas W. Malone in a study of computer games used in education.3 While the arcade games involving fast-moving visuals seem of slight interest to the foreign-language teaching profession,4 adventure games,5 in which words and situations are the currency, seem a promising avenue for educational application. The SPION project, in which I am involved as part of a research group, has been described in detail elsewhere.6 Briefly, SPION is the first game in a computer game system we are designing and implementing for learners of German. It uses techniques of artificial intelligence to create a model of language understanding by computer in an adventure game set in Berlin. We have chosen games as our research vehicle because a game offers a conveniently delimited world with a manageable number of words and contexts. A game structure can be enlarged incrementally by adding language structures and situations, thus enabling us to enlarge our language analysis incrementally also. Applied in foreign language teaching, games offer the possibility of testing the language understanding model concretely, as well as the possibility of being a useful, because highly motivating, learning mode.