The article presents the phenomenon and mechanisms of the development of bilingualism among the nineteenth-century inhabitantsThe article presents the phenomenon and mechanisms of the development of bilingualism among the nineteenth-century inhabitants of villages situated on the Bug River. The issue is principally exemplified by the novel Iwanko [Ivanko] by Leon Kunicki (1828–1873), a writer associated with southern Podlasie (the Włodawa area). Referring to different situational contexts of the characters in the novel, the author of the study has shown the mechanisms of switching linguistic codes: Polish and Ukrainian. An illustration of these complex communication processes is the Greek Catholic (Uniate) community of Horodno village. The...