This paper describes research in understanding system specifications written in natural language. This research involves the implementation of a natural language interface, PHRAN-SPAN, for specifying the abstract behavior of digital systems in restricted English text. A neutral formal representation for the behavior is described using the USC Design Data Structure. A small set of concepts that characterize digital system behavior are presented using this representation. An intermediate

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... ation loosely based on Conceptual Dependency is presented. Its use with a semantic-based parser to translate from English to the formal representation is illustrated by examples.