Characteristics of DART (Didactic Augmented Recursive Transition), an ATN-based system for writing intelligent computer assisted instruction (ICAI) programs that is available on the PLATO system are described. DART allows writing programs in an ATN dialect, compiling them in machine code for the PLATO system, and executing them as if the original code was written in TUTOR (the language of PLATO). Characteristics of DART are: (1) data and program are merged but differently represented; (2) data are organized as semantic networks; (3) percepts and sophisticated input-output interface are available; (4) acts reflect choices for the construction of an instructional theory; (5) DART has its own editor and an on-line authoring guide; (6) DART facilitates stacks and queues but can also handle lists; and (7) DART is a tutor-based system and runs on PLATO. The first operational program written in DART teaches the conjunctions of subordinate classes in a foreign language (Dutch, Italian, English, and French). ELISA (Example of Linguistics Interaction Suitable for Augmentation) is the program that teaches conjunctions in foreign languages. It consists of three main phases--presentation, assessment, and test. By collecting subnetworks, a library of didactic programs can be filled for the development of notions and theories of instruction. One of the main problems in developing intelligent computer assisted teaching programs is the understanding and representation of misconceptions. Adequate tutoring can only be accomplished if misconceptions can be diagnosed and remedied. The syntax of DART is outlined, and part of the concept network of ELISA is graphically displayed. (SW)