## 1 Introduction
### Theoretical Background
#### 1.1.4 CLIL Approach and Its Applications in Tertiary Education
On the other hand, the advocates of CLIL approach argue that \"learners' exposure to discourse in the foreign language should be gradual, starting at a more passive, receptive level, just limited to listen to the teacher's instructions and simple concept checking questions, with the scaffolding of short-length texts, vocabulary lists, information organizers and visual aid\" [63]. It means that even the students with rudimentary knowledge of a foreign language will be able to understand the instructional material. In this way, the students are supposed to skip the unnecessary stage of translating the content from their native tongue into a foreign language. The following query is also frequently raised: who is supposed to teach if CLIL approach is adopted? Universities are unlikely to recruit enough teachers who are able to teach whether a language teacher has enough competence to teach professional content alongside with proficiency in a foreign language. Thus, if a non-bilingual teacher specializing in a particular professional subject gives instructions and explanations in class, language errors are inevitable. Such mistakes can affect the clarity of explanations and, consequently, the students' perception of the professional content. Moreover, they remember the teacher's mistakes on a subconscious level, which can have negative effects on their language proficiency. In some studies, the effectiveness of CLIL is questioned because this approach does not always allow a teacher to achieve a desirable outcome. For instance, in one study CLIL was used in a history class at school. Even though CLIL had a positive effect on the receptive listening skill and an insignificant effect on productive English skills, learners needed more input to gain the same knowledge of the content than they would acquire in a conventional non-CLIL classroom [64]. Thus, some educationalists doubt whether CLIL makes sense at all since more time is needed to teach the same content than in a traditional class. One more issue to address is finding teachers who are equally knowledgeable about the subject matter and the language. In most cases, a language teacher is not knowledgeable enough about professional content, so serious problems are inevitable in a CLIL class. For example, if students have some queries concerning the content, the language teacher might not be in a position to deal with them. The teacher can even make language errors because he/she is not necessarily familiar with the professional terms. In many cases, students specializing in a certain subject are even more knowledgeable about terms than the language teacher, especially when dealing with the words that do not frequently occur in general English. Such deficiencies can result in awkward situations in class, and mistakes made by the teacher can shake students' confidence. A CLIL teacher is supposed to have interdisciplinary knowledge, so educational institutions interested in adopting should set up provisions for short, medium, and long-term teacher training [65]. The extensive knowledge of the subject has always been a very important gauge for the quality of teaching. Thus, if the students notice the teacher's mistakes in class and feel that he/she lacks knowledge of the subject matter, it can furnish his/her image and result in a lack of students' motivation. Therefore, teacher training should be given a lot of attention. One of the solutions to the problem of training the most suitable teacher capable of using CLIL in class is organizing \"regular meetings between content area teachers and language specialists. In those meetings, content teachers were given some guidelines on how to structure and plan a didactic unit within the CLIL approach\" [66]. The same tandem can result in knowledge exchange and cross-fertilization between language specialists and professional content providers. Practical evidence suggests that, in general, interdisciplinary tandems at any level within universities prove to be very useful.