EN[...] The language of the anonymous catechism of 1605 has often been compared to the language of the writings of Sirvydas (±1580-1631), both being distinctly East Lithuanian. The differences between them were meticulously listed by Zinkevicius, who thus refuted the hypothesis that the young Sirvydas was actually the author of the catechism. According to Zinkevieius, the native dialect of the anonymous translator must be traced to the region to the north of Vilnius (1968: passim, 1988: 243), while Sirvydas, who wrote in an East Lithuanian literary language based on the dialect of Vilnius, originated from the area to the west of Anyksciai (1988: 259-266). In this article, we shall discuss one aspect of the language of the anonymous catechism, viz. vowel raising. I intend to deal with the accentuation of this text on a separate occasion. [...].