The in-service teacher training courses in another country within the framework of the Erasmus+ Programme Key Action 1 for Mobility of Learners and Staff helps to improve the quality of the language teaching in our school and promotes the formation of our school partnership network with other European schools. Because of the growing number of applicants for advanced level final exams in languages, the expected high rate of successful language exams and the scheduled measurement of the students' language competences, our school takes a special interest in the modernization of language teaching. We intend to educate our students along EU principles so they will be able to cope with various professional challenges in Europe. It is only possible with the acquirement of two foreign languages. The aim of our project is to increase the competitiveness of our secondary grammar school and to prepare for the new challenges. Today multilingualism is a requirement in Europe, which can only be achieved with high standard language teaching. Therefore, we selected the courses which offer new flexible teaching methods suitable for students' needs and help integrate the cultural references into language lessons. The three applicants teach three different languages in the school, which supports the realization of multilingualism among the students. Each teacher plays an active role in the school life and both their qualifications and professional experience justify the success of our project. The one-year project is carried out in three stages. The first period is dominated by the preparation for the courses, in the second phase we focus on performing the tasks set by the course and in the final part the expected results and goals are assessed. The execution of the project is likely to have a positive impact on both the professional attitude of our language teachers and the effectiveness of the language lessons. Moreover, colleagues teaching other subjects will also benefit from the project. In an indirect way, the success of the project will motivate our students to achieve better academic results. On the short term the quality of the school's pedagogical work will develop together with the employability of the three applicants, which, in the long run, will result in an increase of the competitiveness of our institution.