EN
Attempts at defining 'grammaticality' by stable rules face the problem that the conditions of applying those rules are unstable and changeable. The communicative space that forms the background of linguistic expressions keeps changing as linguistic activity unfolds and that changeability crucially affects the evaluation of any expression that is based on its focusing in the given space. The division of linguistic expressions into correct and incorrect ones on the basis of how they relate to the established rules means that 'ungrammatical' expressions invariably violate some codified constraint. The focusing of linguistic expressions in the communicative space is never stationary, as it has to be adapted to variable circumstances, context, and content, as well as to the variable mental status of the language user.