The article examines the main processes associated with the formation and development of writing in the Old High German period of the formation of the German language. The Old High German period is primarily the period of the formation of the German nation, first within the Frankish state, and later the East Frankish state, ending with the proclamation of the German Empire in 962. Actually, the written tradition of the German language is connected with church life. In the monastery cells, theological treatises, prayers, and psalms were translated into German, historical works were written, and biblical commentaries were compiled for the school and for the education of priests. Monasteries became the centers of education and spiritual life of the early feudal society. At this time, a new form of existence of the German language was formed in the form of a set of territorial dialects. The article notes that The Old High German dialects differ from each other in phonetic, morphological, lexical, and even syntactic aspects. In other words, almost every dialect had its own spelling and phonetic features. However, the unity of the German language was always ensured by the kinship of the dialects, the general trends in the development of their phonetic and grammatical structure, and interaction with a particularly strong influence of the Frankish dialect on others. The development of the graphic system in this period is complex due to the adaptation of the Latin alphabet to German pronunciation. At that time, there was not only a single orthographic norm for the German language in general, but also a single spelling of certain words or morphemes within the framework of a single written document. The main written works of that time are analysed, taking into account the dialectal features of each of them. It has been found that under the influence of Latin, the German script undergoes significant changes, but retains its linguistic independence, particularly in the consonant system.