ENTo consider the interior as a kind of language means to use the term in the sense of "langage", but what exactly does it mean when the interior is treated as a "langage"? What presumptions does it imply, does it open a new perspective on interiors? The author of the paper aims to discuss the conditions for treating the interior as a language and to show its general "grammar": how and what kind of communication is taking place in this case. The "linguistic competence" of the interior is analysed by applying the method of plastic semiotics, based on phenomenological presumptions and intended to reveal the structure and conditions of capturing the non-figuratively communicated meaning. Plastic semiotics shows how interiors can speak by their own means (i.e. without any reference to cultural symbols, styles, figures etc.). The choice and combination of spatial (architectural) components form the interior as a field of expression, where smaller and more flexible elements of furnishing and decor finish to create the totality of meanings of a particular interior. An interior is a whole grasped by the senses of vision, touch, hearing, smell and the sense of space, encompassing all of them; however, what kind of content does it convey? After a short discussion of the possible signifieds of the interior (functional, cognitive and aesthesical), a hypothesis is advanced that the rendering of aesthesical, sensual content is the pure language of interior, which builds the basis for other kinds of communication implemented by the interior.In the paper, an analysis of a fragment of an interior is presented with the aim to show that the interior already means something before becoming a field for some activity and creates a certain mood even without any subjects acting in it. The analysis reveals the sensual logic, on which the interior is based, and which constitutes the first level of the language of the interior, and points out the crucial elements of the meaning of the interior. It is but the first step of the analysis of the meaning of the interior; in order to reveal its entire complex structure, it is necessary to analyse the pragmatic structures of meaning (encompassing both the interior itself and the subjects acting in it) and the cognitive structures of meaning (expressions of existential values and identity). The comprehensive analysis of the totality of meanings of the interior should include movements, activities, smells, sounds, symbols and all the other elements that create the experience of an interior. [From the publication]