The article deals with some linguistic aspects of the Lectures by Peter Trnovsky (1631) as they are reflected in various linguistic planes. In particular, the paper aims to clarify the lingual difference between these lectures and other relics of a religious nature. The lectures are written in a relatively good cultural, north-west-middle type of the Slovak language with numerous components from the Czech language, they are not so appropriate in the Czech language. The fact that the author is a member of the Protestant Church is interesting, because he was supposed to use 'Biblictina' (the language of the Kralicka Bible) while doing his lectures. However, there are sufficiently used all the components typical for cultural language of the Slovak ethnic group.