The article is a presentation of the results of the graphematic analysis of the East-German Acts of the Apostles from 14th century. The author concentrates on the phoneme-grapheme relationship and shows the language features form the East-Middle-German dialectal area in its Silesian tradition found in the translation. All language characteristics are supported with the appropriate examples from the corpus. In the introduction there are also presented some facts combined with the analysed text and with the German eastward expansion.