General remarks on information languages Use of the term "Information Language" (IL) Purposes of an information language-requirements for an information language A general model for the structure of the ensemble of subjects Specializations of the general model Indicative and informative descriptions Analytic vs. synthetic relations Paradigmatic vs. syntagmatic relations Synthetic relations, roles, and categories Comparative list of some schemes given in the literature Principles of construction and state of work Some feature evolving from the comparison of some schemes of role indicators Cumulative and comparative list Sources of relations, role indicators, and categories References