Mamas, we know baby talk may seem silly, but babbling to your newborn is one of the best things you can do for their development. Studies show that constantly talking to your little one can strengthen their language skills and boost their brain power.

Now, new research shows that baby talk isn’t the only way infants learn—mama’s vocal timbre plays a big role, too.

A new study published in Current Biology found that, when mothers engage in baby talk, they shift the way their voice sounds, indicating that their overall timbre—or tone color—may help infants recognize people, places and things. Vocal timbre is the unique quality of your voice that’s distinct from its pitch and intensity (so think a tone that is warm, flat, mellow, breathy or piercing).

“[W]e do know timbre provides an important pointer to different sound sources, thus helping us identify people, animals and objects based on their characteristic auditory ‘fingerprints,’” lead study author Elise Piazza writes in an op-ed for the Washington Post. “So, we wondered whether mothers might unconsciously change their overall fingerprints when talking to their babies, perhaps to signal that an important source of speech, which is highly relevant for learning, is coming their way.

For the study, researchers from Princeton University recorded mamas as they played and read to their 7 to 12-month-old babies, as well as communicated with an adult experimenter. What they learned is that a mother’s tone color naturally—and “possibly unconsciously,” Piazza writes—changes when talking to their infant. And their timbre fingerprint is markedly different when speaking to adults, the experiment showed.

Of the findings, Piazza writes, “Hopefully this is reassuring for parents feeling self-conscious about their own baby talk: However strange you may think you sound, chances are you’re helping your baby learn, and you’re in good company.”

What’s more: The researchers found that this shift in vocal timbre breaks the language barrier. They studied two groups of mamas—one English-speaking, one non-English-speaking—and discovered that, no matter the language spoken, mothers altered their tone color when engaging with their little ones. The shift occurred across nine languages (Spanish, French, Russian, Polish, Hungarian, German, Hebrew, Mandarin and Cantonese), which Piazza says suggests that these timbre changes “may represent a universal form of communication with infants.”

“Being able to identify baby talk across multiple languages could give us rich information about the amount and type of language children hear at home and at preschool … across different cultural environments,” she continues. “This could help researchers and educators predict and improve outcomes such as vocabulary and success in school.”

It’s so fascinating how our voices can have such an important and lasting impact on our infants’ development. You may think it’s silly to jabber on and talk nonsense to your newborn, but really, you’re teaching them so much. So mamas, keep up with all the funny voices. You’re not just making your baby smile, you’re helping their mind grow, too!

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