A team led by Professor Christine Moon of Pacific Lutheran University, tested newborn babies in Tacoma and Stockholm, Sweden. Moon said they played recordings of a distinctly American English vowel sound and a Swedish one, and tested the babies responses by measuring the one thing a day-old baby is really good at: sucking on a pacifier. Their sucking patterns reveal that babies show a familiarity with the vowel sounds of their mother tongue even at birth, suggesting they’ve been listening carefully in utero.
“For them it’s pure sound – they don’t have the ability yet to look at a mouth and see where that sound is coming from. And yet they’re already trying to make sense out of it, and it’s just marvelous,” Moon said.
Previous studies had shown that a late-stage fetus can pick up on the musical components of speech, like melody, rhythm and volume. But Moon said this is the first study to show that a baby in the womb is also picking up on the more nuanced components of language, like vowel sounds.
The findings, co-authored by Dr. Patricia Kuhl of the University of Washington and a Swedish researcher are published in the journal, Acta Paediatrica.
Moon says be careful, though, about trying to give language lessons to an unborn baby. Playing extra sound during pregnancy – think headphones on the belly – might actually disturb a developing fetus. Moon says they hear plenty already.
Researchers use a wired pacifier to test a newborn's familiarity with a vowel sound typical of American English. (Christine Moon / Pacific Lutheran University)