Background and aims: Mother speech is important factor for the child’s speech mastering and cognitive development and socialization. The goal of the study is to reveal acoustic features of speech and elements of nonverbal behavior in “mother-child” dyads during the interaction situation. Participants in the study were 85 dyads with 4-7 years–old children: typically developing (TD n = 40 dyads), children with autism spectrum disorders (ASD n = 25), and children with Down syndrome (DS n=20).

Methods: Perceptual, phonetic, spectrographic analysis of speech and expert analysis of nonverbal behavior in “mother – child” dyads were conducted.

Results: It was shown that mothers of all children are characterized by the initiative when interacting with the child, their speech is loud, clear, grammatically simple, and aimed at stimulating children to the answer. Mothers of TD children more often demonstrated joy than mothers of children with ASD and DS, asked more questions, and clarified the meaning of the children’s utterance. Mothers of children with ASD more frequently answered to children’s replicas and encouraged them. Mothers of DS children were often angry, repeated the question or the same words, addressed to the child by his name. The strategies of mother’s speech behavior correlating with high level of the speech development of TD children are defined. The correlations between features of mother’s speech and clear articulation of children with DS are absent. Mothers of ASD children adapt their speech to the level of the child’s speech and are guided by the severity of autistic disorders of the child, but this strategy does not always lead to progress in the child’s speech development.

Conclusions: Different mother’s speech behavior strategies during interaction with TD children, children with DS and ASD are revealed.
The study is financially supported by Russian Foundation for Basic Research № 17-06-00503а OGN.