The qualitative learning of a foreign language, according to research in the field of linguistics, psychology, pedagogy, didactics, must be carried out based on the didactic principle of conscious acquisition of the subject, which implies the need to use comparative and contrastive analysis in the teaching and learning process. The majority of specialists in linguistics, psychology, pedagogy, language teaching consider phonetics to be of primary importance. Compound phonetic structures with the status of compound monophonemic units make it possible to characterize phonetic and phonemic units not only articulatory, but also structurally: simple and compound units. The influence of the mother tongue or another foreign language learned previously or concurrently, can be the cause of mistakes in the pronunciation of compound monophonemic units. In order to prevent from and correct these mistakes, in the language learning process it is necessary to compare the phonetic and phonological units of the studied language with the respective units of the mother tongue and the other studied foreign language.