At just a few hours old, babies can tell the difference between their native language and a foreign one, showing that they start learning to distinguish the sounds of speech while still in the womb.
“The mother has first dibs on influencing the child’s brain,” says Patricia Kuhl, co-director of the Institute for Learning & Brain Sciences at the University of Washington. “The vowel sounds in her speech are the loudest units and the fetus locks onto them.”
Researchers already knew that newborns arrive can discriminate between language sounds within the first months of life, but this is the first time that language learning has been shown to occur in utero.
“This is the first study that shows fetuses learn prenatally about the particular speech sounds of a mother’s language,” says Christine Moon, a professor of psychology at Pacific Lutheran University. “This study moves the measurable result of experience with speech sounds from six months of age to before birth.”
The team studied 40 infants, about 30 hours old and an even mix of girls and boys, in Tacoma and Stockholm, Sweden. While still in the nursery, the babies listened to vowel sounds in their native tongue and in foreign languages.
Their interest in the sounds was rated by measuring by how long they sucked on a pacifier when listening to unfamiliar or familiar sounds. And, in both countries, the babies sucked longer for the foreign language than they did for their native tongue.
Kuhl says that discovering how babies absorb information could give insights on lifelong learning. “We want to know what magic they put to work in early childhood that adults cannot,” she says. “We can’t waste that early curiosity.”
