This thesis studies and speculates upon the interrelations of artefacts with human and nonhuman agents. These interrelations form assemblages, some of which have emergent properties, becoming manifestations of processes that we cannot fully control or understand. The work started by exploring the theme of hospitality and hostility with the ambition to better understand the ecological complexity of the design process and its results. As an assemblage, this work combines different literary, philosophical and theoretical discourses and traditions with experimental design in order to develop and articulate the concept of device. A device organizes, arranges, frames our environment and thereby defines and limits possibilities of relation. Since relations can only be thought through a so-called natural language such as English, they must be taken into consideration through the process of languaging, understood by Humberto Maturana and Francisco Varela as communication about communication”, and as the most characteristic feature of the human species. My focusing on linguistic and biological phenomena is a response to this concern, in an attempt to understand how this process influences our perception of the world. Through a series of design projects, the thesis examines the potential range of an artefact’s relations. It does so by exploring grammatical associations that affect design onceptualizations, creating tools (prepositiontools) as well as studying and articulating forms of symbiosis that an artefact might develop in and with its environment (¡Pestes!).