Technical aspects of the PLATO system, the language work done on PLATO thus far (specifically in foreign languages), and areas for further research in computer-based language instruction are reviewed. PLATO-IV, designed and implemented by the Computer-Based Educational Research Laboratory of the University of Illinois at Urbana-Champaign, is unusual in being a large interactive system designed solely for instructional use. On-line management and administration of instruction with PLATO-IV has been accomplished by group files and router files, which respond to an increasing need for centralizing instructional sequencing logic. Additional management developments include an instructional management software product called "PLATO Learning Management," developed by Control Data Corporation; various PLATO on-line communications facilities that aid in course administration; and site-management software available with PLATO IV. The only programming language available for interactive use on PLATO IV is TUTOR. Another valuable contribution to language instruction is the TUTOR "answer judging" algorithm. TUTOR has evolved a set of file and database manipulation capabilities and also offers a built-in data collection system. PLATO-compatible micro-processors exist in the form of several intelligent terminals. Most PLATO language materials have been developed by practicing language teachers. Examples of PLATO-based curricula developed for a number of languages are identified. After considering techniques for presenting a single topic through PLATO-based language instruction and evaluation needs for computer materials, attention is directed to future directions, including intelligent processing of grammar and meaning and assessment of grammar competence. (SW)