Baby talk isn’t silly. It’s a serious way of learning.

The timbre of an instrument (whether buzzy, warm or twangy) clearly affects how we experience music, but its role in language is less obvious. When my colleagues and I looked into the tone color of baby talk, we made some surprising discoveries. Mothers change their overall timbre when speaking to babies, almost as if they’re morphing their voice into a different instrument to address these unique little listeners.

Timbre is a complex acoustic feature that helps us distinguish the unique flavors of sounds around us. For example, Barry White’s silky-smooth voice sounds different from Leonard Cohen’s gravelly one or comedian Gilbert Gottfried’s nasally one even if they’re all singing the same note. Contorting the shape of your vocal tract (which goes from your vocal cords all the way up to your lips) results in different resonances, allowing celebrity impersonators and voice-over artists to change their overall timbre.