(Title in Polish - 'Znaczenie prestizu jezyka a pokoleniowe zróznicowanie poziomu inferencji w polszczyznie staroobrzedowców w warunkach rosyjsko-polskiego bilingwizmu z dyglosja'). Russians Old Believers living in Poland in Suwalki-Augustow region constitute a bilingual society. Their bilingualism is connected with diglossia. The domination of one of the codes is determined by the factors characterizing the situation of communication, such as social context, interlocutor and generation of the speaker. In the community of our interest Polish is the 'high' language and the Russian dialect is used for 'low' purposes. It is strictly connected with both codes' prestige level. In some idiolects in the older generation and not numerous in the middle-aged generation the hidden prestige of the dialect equalizes the public prestige of Polish language. The counterbalance of prestige brings about the interference in Polish, especially in the utterances connected with the domain of religion.