Classical work of the famous Norwegian Slavic philologist, founder of descriptive phonetics of Slavic languages ​ ​ Olaf Brock (1867-1961). At the beginning of the book, notes are given on the general physiology of speech, the purpose of which is to emphasize generally recognized phenomena that are of particular importance for understanding the sound system of Slavic speech. The following describes in detail the conditions for the formation of consonants and vowels of speech, as well as combinations of sounds, including in individual Slavic languages.