Acoustical features of vowel-like sounds in vocalizations and vowels in syllabic and in words of 100 children at the age from 3 months till 7 years are analyzed. The material has made 85000 of vowel-like sounds and vowels. Changes of values and variability of duration, pitch and formant frequencies subject to chldren age are revealed. Obtained on a material of Russian data confirm available data in different languages, that reduction of duration of stationary parts and frequency characteristics of vowels is with the years one of the basic trends of development of the acoustic aspect of speech at normally developing children.