Infants seemed to be able to differentiate between two different "D" sounds in Hindi—but only when their tongue movements weren't blocked by a teething device. Christopher Intagliata reports
Babies Move Tongue to Learn New Tongues
"Babies come prepared to learn any of the world's languages." Alison Bruderer, a cognitive scientist at the University of British Columbia. "Which means no matter where they're growing up in the world, their brains are prepared to pick up the language they're listening to around them."
And listen they do. But another key factor to discerning a language’s particular sounds may be for babies to move their tongues as they listen. Bruderer and her colleagues tested that notion by sitting 24 sixth-month-olds in front of a video screen and displaying a checkerboard pattern, while they played one of two tracks: a single, repeated "D" sound in Hindi, <<single d sound>> or two slightly different, alternating "D" sounds. <<alternating d sounds>>
The idea here is that babies have a short attention span, so novel things hold their gaze. And indeed, the babies did stare at the screen longer while the alternating "D"s played than for the single “D”—indicating they could detect the novelty. Until, that is, the researchers blocked the babies' tongue movements by having them suck on a teething device. Then the effect disappeared, with the babies unable to differentiate [single D sound] from [alternating D sounds].
And when the babies used a different teether that did not block tongue movement, they once again appeared to comprehend the difference between the Ds. The study is in the Proceedings of the National Academy of Sciences. [Alison G. Bruderer et al, Sensorimotor influences on speech perception in infancy]
So is it time to pull the pacifier? "At this point I don't think that these data suggest parents should be taking away teethers or soothers. The majority of infants are chewing on something semi-regularly most of the day. And most of these infants do go on to develop speech normally." So not to worry. Bruderer says the research might instead offer insight into how children with oral motor impairments or cleft palate perceive speech...now that we know the tongue really does matter, when first learning a tongue.
[The above text is a transcript of this podcast.]