Résumé :
Plants belong to a particular geographical landscape, but not human beings. Nevertheless, the idea of geographical determinism has never ceased to impose itself in the discussions about collective identities. Throughout these debates about collective belonging, the place of language is central. In the 19th Century, linguistics has constantly been instrumentalized to promote projects of nation and state building, relying on scientific reasoning. Knowing the real place of a language in the universal system of classification meant to know whose state the speakers of this language are or should be citizens, and where a state boundary should be drawn, on scientific basis.
The problem is that the criterions for classifying and distinguishing languages are contradictory and fuzzy, and that the same facts can be interpreted in various ways.
In this paper I will examine various situations of language debates in Central and Eastern Europe to try to highlight the underlying naturalist biases of the discourse on language in academic and folk linguistics. The Eurasianist ideology of the interwar period will be the main topic.