It includses a n u m b e r of specialized tools t h a t consent an easy, graphics-based interaction with the parser. It is shown in particular how a combination of the characteristics of the parser (based on the lexicon a n d on dynamic unification) and of the e n v i r o n m e n t allow a nonspecialized user to explore heuristics t h a t m a y alter the basica control of the system. In this way, for instance, a p s y c h o l i n g.