1. An interaction system for enabling interaction with at least one of several information systems belonging to a single application domain, the at least one information system configured to execute a set of actions on a set of objects characterized by a set of attributes; wherein the interaction system comprises: at least one adapter module configured to access said actions, objects and attributes 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 said several information systems of said application domain; at least one domain module for containing the object classes, attribute classes and action classes common to said several information systems of a single application domain, and phrase setups; each phrase setup having a structure comprising a selection of said object classes, attribute classes and action classes and being provided to be tailored to said at least one information system by applying in the phrase setup: a) the specific object types, action types and attribute categories of said at least one information system corresponding to, respectively, the object, action and attribute classes in said phrase setup, and b) object, action and attribute instantiations obtained from said at least one information system corresponding to, respectively, the object, action and attribute classes in said phrase setup, in order to define a grammar essentially consisting of 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; at least one generic module, connected to the at least one domain module and connectable to said at least one recognition system, for converting said sets of term elements and rules and/or a set of valid user query phrases generated using said sets of term elements and rules into a digital form suitable for being processed by the recognition system for the recognition of user queries and for converting a digital form of a used query, produced by said recognition system in response to said user query and suitable for being processed by a computer, into a phrase according to said grammar and/or into term elements and rules from said sets of term elements and rules; wherein the interaction system is connectable to said at least one information system and to a user interface comprising at least one recognition system, so as to enable the user to interact with the at least one information system by means of user queries processed by said at least one recognition system.