VOCAL (Voice Oriented Curriculum Author Language) is designed to facilitate the authoring of computer assisted curricula which incorporate highly interactive audio and text presentations. Lessons written in VOCAL are intended to be patterned after the style of informal classroom lectures. VOCAL contains features that allow the author to specify audio messages in several formats acceptable to the audio hardware and associated software, and to control the interaction of the audio presentation with material presented visually on the screen of a CRT terminal. This description of VOCAL includes an elaboration of its features, the Browse Mode, the Help System, and operation of the VOCAL Compiler and Interpreter. Appendices include a file format for compiled VOCAL files and implementations of the S Opcode. (CMV)