The topic of the present paper is the relation between linguistics and language education. Put as a question one could ask: 'what benefit can linguistics have for language teaching?'. It will be claimed that as a precondition, language teachers should have more than just marginal insight into theories of natural language. I will try to support this postulate using sentences with modal verbs: based on a certain linguistic theory, illustrations of sentences with modal verbs will be given. These illustrations are thought to be a first step for a didactic preparation (transformation) of explanations given by a linguistic theory for natural language phenomena. As a consequence of the considerations it will be postulated that it is obligatory for the education of teachers to include linguistic modules, since, in line with the hypothesis of this paper, insight into linguistic theories can help: 1) to understand phenomena of natural language and 2) to find a didactical preparation for the phenomena in question.