Dialects is a deep historic notion; the degree of their strength in the different countries is explained by specific historical conditions. Significant territorial differences in vocabulary, phraseology, phonetics and partly grammar on the level of spoken language and dialects form specific peculiarities of the German language. Identifying phonetic, spelling, vocabulary and partly grammatical features of main German dialects in different historical periods and their influence on the formation of the German literary language, the emergence of regional lexical-semantic doublets, ideographic synonyms, their territorial preference and the degree of difference, as well as identifying current trends in this process are the major issues.