The design, specification, and preliminary implementation of the SEMAL language, based upon the Calculus of Self-modifiable Algorithms model of computation is presented. A Calculus of Self-modifiable Algorithms is a universal theory for parallel and intelligent systems, integrating different styles of programming, and applied to a wealth of domains of future generation computers. It has some features from logic, rule-based, procedural, functional, and object-oriented programming. It has been designed to be a relatively universal tool for AI similar to the way Hoare’s Communicating Sequential Processes and Milner’s Calculus of Communicating Systems are basic theories for parallel systems. The formal basis of this approach is described. The model is used to derive a new programming paradigm, so-called cost languages and new computer architectures cost-driven computers. As a representative of cost languages, the SEMAL language is presented.