The phenomenon of the modified register, here termed Foreigner Register, the register of language that is used by language teachers with students of perceived low language proficiency, is discussed. As used by language teachers, Foreigner Register is well formed and simplified or modified in terms of syntax, phonology, and lexis. The characteristics of Foreigner Talk and Foreigner Register as described in six studies are discussed. Generalizations regarding the apparent functions of Foreigner Register in the language class and the possible implications of its use for the language learner are highlighted. It is asserted that Foreigner Register should be supported for use in the language classroom since it facilitates communication and language acquisition. However, it must not be used to the exclusion of other forms since it acts as a comprehension inhibitor by not helping the student to learn to function in an environment of unmodified language. (RW)