This study is a part of longitudinal investigation into children speech formation in the Russianspeaking environment, with the analysis being carriers out on the diff erent factors infl uencing this process. The aim of the study is to analyze the fathers' speech addressed to six-month-old infants. The objects of the research are 8 �father - infant� dyads. The research shows that analyzed characteristics in fathers' speech are diff erent in infant-addressed speech and adult-addressed speech, those diff erences being revealed on intonation pattern, vowels duration, a pitch of stressed vowels in words allocated with a voice, and formant frequency values. On a whole, the obtained data on Russian speech material on acoustic characteristics of fathers' speech addressed to six-month-old infants correspond to similar data on other languages.