The aim of the study was to verify whether the use of the mother tongue when teaching lexical items — false friends in particular — in the foreign language is beneficial to students. It was proved that the methods which require the exclusive use of the target language without referring to the equivalents in the native language lead to better retention of the words` meanings in the case of false cognates; however, the importance of techniques of practising new lexical items shall not be ignored. The consequences of using only the target language need further studies as it was observed that students taught with the exclusive use of English were not as sensitive towards transfer errors as students taught with the help of Polish equivalents.Cel...