Bilingualism is considered as a phenomenon of culture in the context of language contact. A comparative analysis of the phenomena of bilingualism and biculturality is carried out. It is shown that, while creating prerequisites for the biculturality of the subject, bilingualism, however, does not provide it. The function of choosing a language as a choice of social roles, which opens up for a bilingual subject, is shown. The leading role of language choice in the context of communicative adaptation is substantiated. The criteria of language choice are considered: social, socio-psychological and occasional-situational. Adaptive strategies are modelled in relation to speech behaviour in a communicative situation. The significance of the balance between the linguistic and ethnic identity of the subject, on the one hand, and his desire to meet the linguistic expectations of the interlocutor, on the other, is shown. The role of bilingualism as a factor in the emphasis of reflection on language is substantiated. It is shown that in a bilingual context the problems of language development go beyond boundaries of linguistics and become а subject of wide social discussions. The role of bilingualism in literary creativity is revealed, the value of using lexemes of the second language as a tool for enriching artistic expressiveness is shown. It is proved that the more languages in the applied thesaurus of the subject, the richer the emotional palette of his perception of the world. The potential of the language is revealed in relation to not only expressing, but also reflecting emotions, which expands the range of reflexive comprehension of the emotional sphere. On the material of the texts of poetic culture in Belarus, the expansion of the range of expressive possibilities of bilingual subject is substantiated and its significance for the development of artistic culture is demonstrated. The specificity of bilingual subject’s thinking is revealed. Firstly, it is substantiated that in different linguistic projections, a particular fragment of reality can not only turn with its different facets, but in general be configured in a different way, expanding the interpretive potential of the subject and his cognitive capabilities. Thus, the picture of the world of a bilingual subject turns out to be more multidimensional and more plastic. Secondly, it is shown that the possibility of switching the language code, open to a bilingual subject, entails the possibility of appealing to the values of both cultures behind the languages. The thinking of a bilingual subject turns out to be open in relation to more than one option for perceiving reality, which provides not only a richness of perception, but also an expansion of the range of understanding. Such open thinking also means expanding the possibilities of mutual understanding in cross-cultural dialogue, which ensures the effectiveness of both interpersonal communications and the success of international interactions.