The aim of the article is to present the importance of linguistic knowledge (linguistic concepts) in the process of teaching Polish as a foreign language. The awareness of its own identity as a science allows glottodidactics to make a sensible interaction with related areas. Concepts originating from other fields of knowledge, e.g. linguistics and psychology, are the source of stimuli and inspiration; they support glottodidactics. Interdisciplinarity causes the expansion of the research field and is a sign of time in modern science. Both linguistics and glottodidactics have a common subject of research, which is language. The difference concerns the perspective of the analysis being carried out: the definition of the concept and its descrip...