The findings come from BabyLab, a child development research team at the Polish Academy of Sciences' Institute of Psychology, a state-funded network of research institutes based in Warsaw.
Researchers say speech is a highly complex motor task. Producing a single syllable requires coordinated work by close to 80 muscles, making early speech development challenging for infants.
The team argues that progress in language can be supported by broader physical milestones such as sitting independently and walking.
Two BabyLab researchers, Dr. Joanna Duda-Goławska and Dr. Zuzanna Laudańska, set out to test whether vocalising activates parts of the body not directly involved in the vocal tract.
A team led by Prof. Przemysław Tomalski studied around 100 children aged 4 to 24 months as part of the MOVIN project.
Using accelerometers, motion sensors that measure movement, researchers tracked infants’ limb activity during free play while also recording each vocalisation, meaning speech-like sounds that come before clear words.
The analysis found a strong increase in movement in both arms and legs immediately before a vocalisation began. The heightened movement continued during the vocalisation and then dropped sharply as it ended.
Tomalski said the results could help explain how physical development difficulties may translate into language delays.
"Both of these areas of development are closely connected, but until now we did not know the basic mechanism that links them," he said. "Our study precisely shows what the relationship between speech and motor development involves, that is, how an infant’s physical capabilities limit progress in learning to speak.”
He added that the work points to new directions for designing interventions to prevent developmental difficulties.
Laudańska said the results also shed light on why adults often gesture while talking.
"Our results indicate that gesticulation, which often involuntarily accompanies speech in adults, has its source in infancy, when vocalising is strongly coupled with short movements of the arms and legs,” she said.
Writing in the journal Scientific Reports, the researchers also note that voice production is closely tied to breathing movements and that body position shapes vocal sounds not only in humans, but also in other species.
(rt/gs)
Source: naukawpolsce.pl