Abstract: The multicomponent structure of the Grand Duchy of Lithuania (GDL) has repeatedly been a subject of historical research. Separation of the cultural and historicregions of "Litva," "Ruś," "Žamojć" from the integral body of the GDL has already become a historiographical tradition. However, it is more difficult to delimit e Belarusian and Ukrainian sociocultural and sociolinguistic complexes of the sixteenth-seventeenth centuries.