The article aims to identify core competencies in teaching a foreign language. Particular attention is paid to mediation, as one of the types of speech activity. The article discloses the definitions of the concepts of “mediation”, “intercultural competence”, presents the main types of competencies, the structure of intercultural competence, the classification of mediation activities, forms of mediation. The article attempts to develop criteria and propose tasks in which both competencies are related. Examples of role-playing tasks in English for high-scholars are given. Materials of the article may help foreign language teachers working in the middle school.