The paper analyses the linguistic aspect of wall-inscriptions of the 12th – 15th centuries, foremost biblical and liturgical quotations, within the composition of Old Russian church wall-paintings. Paleographic, orthographic and textual features of the inscriptions characterize them as literary texts, which reflect, on the one hand, the norms of the Church Slavonic language used in medieval Russia, and on the other hand, a number of regional features (Novgorod, Staraya Ladoga Pskov, Polotsk). Together with the iconographic evidence, the wall-inscriptions can sometimes testify to the participation of local masters, and in some cases they can specify the creation date of the wall-paintings.