STEP Application Protocols (APs) are often very large and complicated general descriptions of different domains mainly within the manufacturing industry. STEP AP's are expressed in the EXPRESS language which is a static modeling language of Entity-Relationship type. Users of STEP AP have often large problems to understand the whole AP and therefore they need a tool which helps them to validate the STEP AP. The tool we are proposing is a natural language English paraphraser of the STEP AP. The VOLVEX system supports automatically building a domain lexicon from one STEP AP and with this lexicon automatically translate one arbitrary STEP AP EXPRESS file into a Prolog based format to be used by a Natural Language Generator called ASTROGEN. The translation from EXPRESS format to EXPRESS Prolog format and the construction of the domain lexicon is carried out by a set of Perl programs.