Baby talk is more sophisticated than you might think

Mothers use a similar tone across many diverse languages.
Mothers use a similar tone across many diverse languages. Photo: Shutterstock

It might just sound like silly chatter, but baby talk is a lot more sophisticated than you might think.

And it's universal.

Researchers examined the way 24 mums, who spoke in 10 different languages, talked to their infants and discovered that baby talk was instinctive.

Mums, the world over, use a distinct form of speech including raising the pitch of their voice, speaking in short repetitive phrases and they shift the timbre of their voice in a rather specific way. Timbre can be defined as the character or quality of a voice that makes it unique to each person such as huskiness or nasal tones.

"We use timbre, the tone colour or the unique quality of a sound, all the time to distinguish people, animals, and instruments," Elise Piazza, a researcher from Princeton University said.

"We found that mothers alter this basic quality of their voices when speaking to infants, and they do so in a highly consistent way across many diverse languages."

And while they didn't research dads as well, they reckon the results would be similar for them too.

Piazza and her colleagues at the Princeton Baby Lab, started out by recording 12 English-speaking mums while they played with and read to their seven to 12-month-old children. In comparison, they also recorded them speaking to adults.

"We basically brought mothers into the lab and had them play with and read to their own babies, just like they would at home," said Piazza told The Guardian.

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They wanted to examine the way children learned to detect the different voices around them and decided to first focus on the unconscious vocal adjustments parents made while chatting to their infants.

Using a special computer program, researchers were able to measure the differences in each person's voice.

They found that the computer system could not only differentiate between different mothers' voices, in 70 per cent of cases it could reliably differentiate between when a mum was speaking to an adult or an infant.

Interestingly, using an approach called machine learning, it was found that a computer could learn to distinguish between baby talk and normal talk based on just one second of speech data.

Next, researchers examined the language variance in women who spoke in nine different languages, including Cantonese, Mandarin, Hebrew, Spanish, Russian, Polish, French, German and Hungarian. And what they discovered was the same alterations in speech were highly consistent across languages.

"The machine algorithm, when trained on English data alone, could immediately distinguish adult-directed from infant-directed speech in a test set of non-English recordings and vice versa when trained on non-English data, showing strong generalizability of this effect across languages," Piazza said in the report released in journal Current Biology.

"Thus, shifts in timbre between adult-directed and infant-directed speech may represent a universal form of communication that mothers implicitly use to engage their babies and support their language learning."