Acoustic aspects of the formation of speech in children in the third year of life.

This study covers the third year of life as part of a longitudinal investigation of the establishment of speech in Russian children performed on the basis of listener, phonetic, and instrumented acoustical analysis. The present report addresses the establishment of those additional acoustic and phonetic characteristics in children's speech which allow speech recognition. This is the first instrumented analysis in Russian children with statistical assessment of the dynamics of vowel formants in children's words, of the establishment of characteristics (stress, lack of stress), opposition (palatalization, lack of palatalization of consonants), and voice onset time for plosive consonants. The results showed that recognition of children's words by listeners with a high probability of success resulted from the formation of a system of acoustically stable properties in the children's speech which together provide informational adequacy for verbal communication.