1. An interaction system for enabling a user of at least one information system belonging to an application domain to interact with said at least one information system, so that the at least one information system executes a set of actions on a set of objects characterized by a set of attributes; wherein said actions, objects and attributes are classifiable in action types, object types and attribute categories specific to each one of said at least one information system, and in action classes, object classes and attribute classes common to several information systems of said application domain, said interaction system is connectable to said at least one information system, said interaction system is also connectable to a user interface comprising at least one recognition system, so as to enable the user to interact with that said at least one information system by means of user queries processed by said at least one recognition system, and wherein said interaction system comprises at least one domain module for containing the object classes, attribute classes and action classes of said application domain, and phrase setups having a structure based on said object classes, attribute classes and action classes and provided to be tailored to said at least one information system of said application domain by applying in said phrase setups the specific object types, action types and attribute categories of said at least one information system corresponding to the object, action and attribute classes in said phrase setups and object, action and attribute instantiations obtained from said at least one information system corresponding to the object, action and attribute classes in said phrase setups, in order to define a grammar essentially consisting in a set of term elements comprising the object, attribute and action instantiations obtained from said at least one information system and a set of rules governing the use of these term elements in a set of valid user query phrases for interaction between the user and said at least one information system through said recognition and interaction systems.