Starting from the initial (topical) issue of language diversity and criteria for demarcation
of particular languages, this paper analyzes the essence of language, i.e. the essential function of language. On the one hand, the analysis deals with the communicational function
of language, which is generally recognized as its fundamental function; on the other hand,
however, language is analyzed as a means of social identification, i.e. as a cohesion factor
in the foundation and preservation of identity („identitätsstiftende Funktion“). The paper
provides arguments that this function is on, more or less, the same level of importance as the
communicational function with which it is mostly inseparably connected. Only when both
these functions are regarded as equally important, it is possible to understand the logic of
differentiation of languages, of language diversity in the world, and of drawing boundaries
between languages, even where perfunctory observers may see these languages as identical
or only insignificantly distinct