CONSTRUCTOR: A natural language interface based on attribute grammar. The paper gives an overview of a natural language interface currently being developed at the Research Group on Theory of Automata at the Hungarian Academy of Sciences in collaboration with the Attila József University, Szeged. The interface supports natural language communication between the user issuing commands as steps in plane geometry constructions and the actual graphical presentation. The natural language interface named CONSTRUCTOR is described and the experiences of the authors are outlined with a view to generalizing the results thus obtained.