What Baby Talk Does for Infants’ Language Development

So-called baby talk is characterized by high pitch, slow speed and exaggerated pronunciation. This kind of speech not only appeals to babies, but may actually help them learn to produce speech themselves. The findings of a new study from the University of Florida and McGill University in Canada suggest that by mimicking the sounds made by the smaller vocal tract of an infant, adults are teaching babies how words should sound.

“It’s not just goo-goo ga-ga,” Matthew Masapollo, one of the study’s coauthors, told TheDoctor. “It seems to stimulate motor production of speech, not just the perception of speech.”

By imitating the sounds produced by babies’ small vocal tracts, baby-talking adults help infants learn how words should sound.

The study comprised two experiments. Data from 24 babies aged six- to seven-months-old were analyzed for the first experiment. The babies had a strong preference for vowel sounds synthesized by a vocal tract that sounded like a smaller tract. In the first experiment, both the infant and adult vocal tracts had high frequencies.

For the second experiment, data from 41 five-to-seven-month old babies were analyzed. In this experiment, the frequency was adjusted to higher and lower ranges. The babies again demonstrated a preference for vowel sounds synthesized by a vocal tract similar to their own, versus that of an adult. “As babies reach 6.5 months of age, infants display a preference for acoustic vowel sounds that specify a smaller vocal tract,” the researchers said.

The findings suggest that as babies gain control of their voices and make the transition from babbling to beginning to form words, infant-like sounds become more appealing. “ Right as they transition from the babbling stage is when we see this correlation,” Linda Polka, lead author on the study, told TheDoctor.

“In this experiment, we tried to pin down what exactly about an infant’s voice is so captivating to babies,” said Masapollo, an assistant professor in the department of speech, language, and hearing sciences at the University of Florida. It is possible the babies just like higher pitch of the infant vocal tract. Infants may also like infant-like speech because it is easier to process and similar to the sounds they themselves are beginning to make.

“Sometimes parents think they are talking down to their baby [when they talk baby talk]… but that should not be a concern,” Polka, a professor in the School of Communication Sciences and Disorders at McGill University in Canada, explained.

Parents should pay attention to how their babies respond to them. And they don’t need to worry they will do something detrimental to their child’s speech development by talking to them. Babies need to be encouraged as they are starting to produce sound. “They like to hear their own voice, and this will start them exploring. We are priming them to process their own voice,” she added.

Future studies may explore the kinds of vocalizations and sounds infants prefer. For example, whether they like isolated vowel and consonant syllables over infant non-speech vocalizations. These studies could help researchers determine if infants’ preference for sounds made by a small vocal tract is phonetic in nature or due to acoustic properties common to both infant speech and nonspeech vocalizations.

The study is published in the Journal of Speech, Language, and Hearing Research.