Some people refuse to use baby talk with babies. The sing-song repetition of cute nonsense words commonly spoken by adults to infants—and pets—can have a grating quality that makes some people cringe, like nails on a chalkboard. It can seem like the adults are regressing to a more primordial, infantile version of themselves.
But baby talk may actually help babies learn to talk.
These are the findings of a study recently published in the journal Developmental Science. Researchers from the University of the Sunshine Coast in Queensland, Australia, wanted to know if the exaggerated pitches and other sounds typical of what’s technically termed “infant-directed speech,” or IDS, could help babies learn to tell the difference between one vowel sound and another. Vowel sounds are the ones most commonly exaggerated by adults in baby talk, research has shown, but this practice isn’t unique to infant-directed speech. Humans also tend to draw out vowel sounds when articulating in noisy environments and talking with non-native speakers.
Whether baby talk helps babies learn language has been a somewhat controversial subject. “Previous research has consistently shown that infants prefer to listen to IDS,” said researcher Varghese Peter in a statement. “But whether it has any significance beyond this is under debate.”
Read more: “When Kids Talk to Machines”
Some studies have already shown correlation: That infants whose parents use exaggerated vowel sounds appear to have better language perception abilities and larger vocabularies later. But not all baby talk features long sing-songy vowels. For example, parents who speak Dutch, Norwegian, and Danish are less likely to use them when talking to infants. Exaggerated vowels can also blur the distinctions between one vowel and the next, which could, in theory, make it harder for babies to learn how to understand and use them.
To investigate, Peter and his colleagues recruited 22 Australian adults, 24 4-month-old infants and 21 9-month-old infants and brought them into the lab. Then they played recordings of a single Australian-English mother talking in baby talk with her 9-month-old infant and in regular adult speech with someone else and recorded what was happening in the study participants’ brains using EEG recordings when they were listening to specific vowel sounds spoken in the language of baby talk. They chose these particular ages because the first year of life is critical for language development— a time when babies become more attuned to native language sounds and less sensitive to non-native ones. In the first four months, babies are mostly learning acoustic pattern matching, while the perception of different vowel categories is thought to advance in a major way between six and nine months of age.
What the team found is that 4-month-old babies had stronger, more “mature” responses to vowels spoken in baby-talk-ese—what they called a “mature” response—whereas the brains of adults and 9-month-old babies responded similarly to both baby talk and regular speech. “When they heard vowels spoken in adult speech, their brains showed a less advanced response. However, when they heard the same vowels spoken in infant-directed speech, their brains produced a more advanced response, similar to that seen in older infants and adults,” explained Peter, referring to the 4-month-olds.
“In other words,” he continued, “‘baby talk’ isn’t silly at all; it may support early language learning from as young as four months of age.”The scientists note that it’s possible vowel exaggeration isn’t the only part of baby speech that could be responsible for the ways the youngest babies responded to baby talk. Typically, exaggerated vowels coincide with higher pitches and greater pitch ranges, which could have also contributed. Another caveat: The authors focused on a specific contrast between “a” sounds and “i” sounds. For more difficult vowel contrasts, the benefits of using baby talk could extend beyond nine months, they point out.
What they found may not prove that every goo goo gaga creates a genius, but it does suggest that this linguistic nonsense has real meaning to those who actually need to hear it. 
Lead art: Design_Stock7 / Shutterstock
