Execution architectures include Directly Executed Languages, or DEL's, which are tailored to particular combinations of software and hardware technologies. In this paper, we review the general notion of DEL's, and show how they compare to traditional instruction set architectures. We focus on general techniques for synthesizing DEL's rather than performance questions per se, however. There are four aspects to this design problem: Naming: relating identifiers to objects. Formatting: associating objects to arguments/results. Control: specifying the order of interpretation. Function: operating on objects identified by the naming and format mechanisms, in the order specified by the control mechanism. A simple directly executed language for FORTRAN-II (called DELtran) is used to illustrate our approach to execution architecture design. Copyright © 1983 by The Institute of Electrical and Electronics Engineers, Inc.