ond-language teachers have to deal continuously is that of student language errors. Their prevalence is undeniable, and teachers have generally been unsuccessful in altering the situation whether they have sought to eliminate them by teaching grammar rules, by drilling new linguistic habits, by constant correction, or by threatening references to pop quizzes and/or poor grades. This reality of learner language errors, confronted by the traditionally negative image of a second-language class as one in which only perfect language is acceptable, creates a conflict often frustrating to students and teachers alike. Basically, two types of student language errors require teacher attention. The first occurs during drill or exercise practice; the second, during communication practice. The first involves the manipulation of linguistic patterns and forms. The second requires the use of these learned linguistic patterns and forms to convey a message. If an error occurs during the first activity, most likely the error results from an incomplete comprehension of the grammatical concept being practiced. However, if an error occurs as the learner attempts to communicate, the diagnosis is not so clear. Fault may not result from any lack of knowledge or incomplete comprehension.1 In fact, students may very well receive an almost perfect score on a drill or exercise only to commit repeated errors as they attempt to use the same structures to communicate.2 The obvious implication of this very common occurrence is that the causes of errors cannot be explained on the basis of an incomplete knowledge of grammar.3 Errors cannot be purged from future communications by just one more dose of grammar, since the cause is not due,