Bilingualism and multilingualism in education has become a reality in the modern multi-cultural world. In recent years, there have been numerous studies proving benefits from bilingual and multilingual approaches in education. Proficiency in second or third languages has many benefits starting from excellence in academic studies and easier access to global information resources and ending with personal awareness of cultural diversity of the world and global mobility. There is overwhelming evidence that English and German are the most popular languages chosen for the Unified State Exam in a foreign language in Russia. The study shows that a worthwhile investment of time and effort into grammatical aspect of language acquisition is of great value. The research is based on the data collected in an experiment involving 38 senior students of gymnasium 6 in Ivanteevka (Moscow Region, Russia). The result of the experiment proves the efficiency of the translanguaging approach to teaching English or German grammar. The successful formation of grammar skills in oral and written speech is based on the comparative analysis of the languages (L1, L2, L3). The mistakes which were predetermined by the differences in grammatical features of the target languages were eliminated by laying emphasis on developing mostly productive rather than reproductive skills. The cognitive exercises used the experiment enlarged the students` meta-disciplinary knowledge and helped them to master analytical skills. By comparing cultural, linguistic and social phenomena existing in L1, L2 and L3 the experimentees came to realize their belonging to the global community and the necessity of application of their language skills to successfully function as an equal member of this community. This approach could be widely used in comprehensive schools in the Russian Federation, adding to the positive effects on intellectual growth and enhancing students` linguistic, emotional and personal development.