The article presents data on the features of the language development of twins and single-tons at 3-4 years of age. The aim of study was to determine acoustic characteristics of speech in the first and second child in pair‘s monozygotic and dizygotic twins and in speech of singletons child‘s. A 5 twin pairs and control group of 10 singletons participated in the present study. The study of a cohort of all twin children born between 1 January 2010 and 31 May 2011 was carried out at Saint-Petersburg Hospital №17. Twins and singletons were born after at least 32 weeks gestation and without identifiable neurological abnormality. The following methods were used: children voice recording (model situation: the game with mother, reading a book by mother, play with laptop); perceptual analysis of speech signals (n = 24, the auditor); acoustic spectrographic analysis («Cool Edit Pro 2.0»). The study confirmed the hypothesis that 3-4 years old twins have significantly higher the pitch values than singletons. The pitch va