The aim of the project conducted by dr. Jacopo Saturno in cooperation with prof. Przemysław Gębal is to empirically document the process of acquisition of Polish as a foreign language by speakers of Russian. This identification identifies two important groups, i.e. contemporary Slavic immigration to Poland (Ukrainians, Belarusians, Russians) and foreign students of Russian as a foreign language (unlike Polish, Russian is offered as a foreign language by most European universities). Of course, these two groups differ from each other in various respects, but they also have a lot in common. First of all, it is the knowledge of Russian, which is relatively close to Polish in terms of the grammatical and lexical system. The similarity makes it easier to recognise words and grammatical structures of the Polish language, but it may also result in so-called "interference" errors or (especially in the case of Eastern Slavs) the impression that the Polish language does not need to be learnt seriously, because "it can be understood without difficulty". The first results, pending publication, show that knowledge of Russian significantly speeds up and facilitates the process of Polish language acquisition. An innovative didactic-methodical concept is currently being developed to promote Polish as a foreign language among non-Slavic students with knowledge of Russian, in line with the assumptions of the European language policy supporting multilingualism.