For the second language student, proficiency is a measure of what tasks can be accomplished with acquired language and how well they can be accomplished. The necessity for specification of functional proficiency arose, and resulted in the publication of guidelines by the American Council on the Teaching of Foreign Languages (ACTFL)'s guidelines delineating functional proficiency in five areas: speaking, writing, reading, listening, and culture. This represents a paradigm shift, as communication has become the focus of language instruction. Applying instructional systems design to a proficiency oriented foreign language program is discussed in terms of the following guidelines: (1) use the ACTFL proficiency guidelines; (2) write specific performance objectives and criterion referenced test items before developing instruction; (3) make the classroom learner-centered; (4) integrate instructional materials and media; and (5) evaluate the program: both formative and summative evaluation can improve the effectiveness of foreign language instruction. (Contains 12 references.) (MAS)