Why Adults Instinctively Switch to Baby Talk When Interacting With an Infant

Dr. Erica Brozovsky of the PBS series Otherwords explained the linguistic science behind baby talk, or infant-directed speech (IDS), specifically why adults across cultures instinctively switch to this exaggerated speech style when interacting with infants.

Speech rate slows down with more pauses between words. Pitch tends to be higher with more variation. Vowels are often exaggerated. Grammar becomes simplified and words get repeated, specifically nouns and verbs. And the behavior is more or less involuntary. Nobody decides to baby talk; it just kind of happens.

Despite its instinctive nature, a stigma remained that IDS was a quirk of Western industrialized societies rather than a universal human trait.

By the mid 2000s, the majority of linguists and child psychologists agreed that baby talk is beneficial for language development. But a different stigma remained, that instead of it being a universal human trait, IDS was in fact a quirk of Western industrialized nations, a luxury of privileged white parents with plenty of free time and obsession with academic performance.

Brozovsky addressed why babies respond to IDS and how it may support their linguistic development.

Studies have found that a high-pitched voice will grab and hold a baby’s attention better than a lower-pitched one. In fact, they seem to prefer voices that are around the same frequency of their own vocal tracts, a preference that doesn’t develop until they’re old enough to make sounds of their own. …

Humans also use a similar register of speech when talking to animals.

Smooth, high-pitched speech signifies friendliness and vulnerability. This association is so deep that it crosses the boundaries between species.

How Babies Learn to Talk