Abstract Open University students learn on their own with little or no tutorial help. For use with a new Introductory course in Computing, the Open University has designed a new programming language to cope with this special situation. The language supports a variety of teaching objectives. This paper describes the design of the computing environment and command language within which the language operates. The environment has to meet certain design criteria which will enable naive users to interact usefully, with little assistance, with a computer system. We describe the sophisticated requirements of the computing course and how the new environment helps students to learn computing concepts and give a sample of typical terminal dialogue. Some implications and developments for the future are outlined.