Buzz
Understanding speech involves more than just hearing—movement might also play a key role, according to a recent study from the University of British Columbia.
In a study published in the journal PNAS, audiologists and psychologists discovered that infants who cannot move their tongues struggle to differentiate between speech-related sounds. The research involved 24 six-month-old babies who were presented with two different “d” sounds from Hindi, which they were asked to distinguish. Hindi was chosen because prior studies show that babies as young as one month old can differentiate speech sounds, and English-learning babies would not have encountered these specific sounds before.
All babies in the study used teething toys, but half of them had toys that prevented tongue movement necessary to form a “d” sound, while the other half did not. The researchers measured the babies' ability to recognize sound differences by observing how long they looked at a virtual checkerboard when alternating sounds were played versus when only one sound played. If the babies gazed longer during the alternating sounds, the researchers concluded they could distinguish between the sounds.
In a series of tests, babies who used teething toys that restricted their tongue movement couldn’t distinguish between the “d” sounds, while babies who were able to move their tongues could differentiate between them. This suggests that understanding speech is not just about hearing, but also involves motor development, influencing how well children perceive speech.
These results may be particularly relevant for children with conditions like a cleft palate, which can limit their ability to move their tongues in speech-related ways. This finding should encourage further studies on how much time children need to spend without toys or other obstacles, in order to allow for free tongue movement.
