Speech development in the first year of life is closely linked to movements of the entire body, and infants’ first sounds are almost always accompanied by intense limb activity, according to researchers from the BabyLab team at the Institute of Psychology of the Polish Academy of Sciences.
In a paper published in Scientific Reports, the researchers noted that speaking is a highly complex motor activity and that producing a single syllable requires the coordinated work of nearly 80 muscles. For infants, mastering such complex sequences is particularly challenging, and speech development is supported by the acquisition of other motor skills, such as sitting up or walking.
Joanna Duda-Goławska, PhD, and Zuzanna Laudańska, PhD, set out to examine whether vocalisation activates parts of the body not directly related to the articulatory system.
As part of the MOVIN project, the team led by Professor Przemysław Tomalski studied around 100 children aged between four and 24 months. Using accelerometers, researchers measured limb activity during free play while simultaneously recording each infant’s vocalisations.
The analysis showed strong activation of both arms and legs immediately before vocalisation began. The movement continued during vocalisation and decreased significantly once it ended.
Professor Tomalski said the findings help clarify how motor development difficulties may affect speech development.
“Both of these areas of development are closely related, but so far we did not know the basic mechanism that connects them. Our study precisely shows the relationship between speech and motor development, i.e. how the capabilities of the infant's body limit progress in learning speech,” Tomalski said. He added that the discovery opens new directions for designing interventions aimed at preventing developmental difficulties.
Zuzanna Laudańska highlighted the evolutionary and developmental dimension of gesturing.
“Our results (...) indicate that gesturing, which often involuntarily accompanies speech in adults, has its origins in infancy, when vocalisation is strongly coupled with short movements of the arms and legs,” she said.
The researchers also noted that voice production is closely linked to movements of the respiratory system and that body position influences sounds not only in humans but also in other species.
The research was conducted under the SONATA BIS and OPUS grants led by Professor Tomalski and funded by the Polish National Science Centre. The analyses were carried out in cooperation with the University of Heidelberg, with support from the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG). (PAP)
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