This work forms part of a longitudinal study of speech development in Russian children. Its aim was to investigate the speech skills in 4-5 years old children through the characteristics of these skills realization in dialogues with adults. The following groups were compared: children brought up in families with no development disorders (the norm group); children having had heavy neurological disorders during the first year of life (the risk group); and children from Children's home (the deprivation group). The study comprised a comparison of lexical, grammatical and phonetic characteristics of the children vocabulary and of the children replies in dialogues with adults. It was shown that in the dialogue interaction pattern the norm group children implemented their developed speech skills successfully. Speech interaction with an adult in the risk group children was impeded due to the low speech development level. The deprived group children verbal communication skills are not formed.