- You know it's cringe, but you just can't help it.

You see a baby and automatically start talking like a buffoon.

- Little baby, (speaking Gibberi How are you little Jack?

- Oh, little Davey, little Davey.

Peekaboo, peekaboo.

- Many people call this baby tal but it's not to be confused with the nonsensical goo-goo gaga sounds babies make.

(audience laughing) (actress baby-talking) - It's also been called motherese or parentese.

And for many years, child psychologists discouraged the practice, warning parents that it could slow language development and teach bad speech habits.

Are you learning bad speech habi Yes, you are.

Yes, you are.

But that perspective has changed thanks to a number of linguistic, neurological, and cultural studies into what is scientificall known as infant-directed speech.

By looking into the minds of both babies and adults, some fascinating discoveries have been made about how it impacts language ac what its evolutionary roots migh and even why we do it with our d I'm Dr.

Erica Brozovsky, and this is "Otherwords."

(bright upbeat music) - [Announcer] "Otherwords."

- No two people baby talk in the exact same way, but there are some common featur 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.

Like a lot of linguistic phenome when something occurs instinctiv there tends to be a lot going on under the hood.

And infant-directed speech is no exception.

Studies have found that a high-pitched voice will grab and hold baby's attent 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' develop until they're old enough to make sounds of their own.

It's almost like adults ar doing an imitation of the infant and the infant likes it.

There's also an emotional elemen Smooth, high-pitched speech signifies friendliness and vulne This association is so deep that it crosses the boundaries between species.

Humans can correctly identify th behind a wide variety of animal from pigs to alligators.

This may be why our dogs and cat tend to also like baby talk, and why romantic partners will use it with each other.

In fact, research shows that couples that do it tend to have stronger, healthier relationships.

Once the speaker has the baby's trust and attention, the other elements of IDS impart valuable linguistic infor A slower tempo allows the infant to grasp the rhythm and intonation patterns of the language, known as prosody.

Exaggerated vowels may also high the differences between phonemes Repetition encourages the retention of keywords.

And despite the fear that i could teach bad speech habits, baby talk almost never employs incorrect grammar or pronunciati Various studies have shown that IDS improves or accelerates certain language skills in young children, like vocabulary, sound different and word boundary perception.

One interesting benefit is the d of baby's preference for trochai There seems to be a natural inclination in infants to pay special attention to word with a stressed-unstressed rhythm like bottle, mama, and baby, perhaps because they sound like their mother's heartbeat, (imitates heartbeat).

But IDS helps them also focus on the more difficult iambic words like believe, guitar, and collect.

But if baby talk is meant to help infants learn to speak, why would we use it with our cats and dogs?

- Yes, you're a good girl.

You're a good girl, you're so wo - You stay just the way you are, because you are a perfect man and I'm going to take you home and get you something to eat.

- Little lumpy dump-dumps won't have his daddy to give him washy scrubby.

- Well, we don't, not exactly.

Studies show that pets really do prefer the high register and fluctuating pitch of baby ta And repetition of keywords can help them learn vocabulary, like walk and bone.

Do you want a walk?

Do you want to go for a walk?

A walk?

Let's go for a walk.

However, pet-directed speech tends to omit those features of IDS associated with speech pr like exaggerated vowels and pros And it's more likely to incorpor incorrect pronunciation and gram That's why my little baby bear can't have cheeseburger.

By the mid 2000s, the majority of linguists and child psychologists agreed that baby talk is beneficial for language devel But a different stigma remained, that instead of it being a universal human trait, IDS was in fact a quirk o Western industrialized nations, a luxury of privileged white par with plenty of free time and obsession with academic perf It is true that the vas majority of 20th century researc into IDS focused on so-called WEIRD countries, Western, educated, industrialize rich, and democratic.

And several researchers claim to have found cultures that either don't use infant-directed speech or don't speak directly to their infants at all, like the Tsimane of Bolivia, the Yucatec Maya, and the Kaluli of Papa New Guine But in 2022, the Harvard Music L visited dozens of diverse communities around the globe and recorded adults interacting with children.

(parent 1 speaking foreign langu (parent 2 speaking foreign langu - [Parent 3] It's okay Caitlin.

You're okay, Caitlin.

- After analyzing hundreds of hours of audio, they concluded that in every single culture they surveyed, from Beijing to South Sudan, whether urban or rural, industrialized o hunter-gatherer, adults did use a special form of speech when addressing infants, which shared a lot of the charac of what we call baby talk.

To drive the point home, the researchers created an online game called Who's List That asked people to listen to audio recordings and guess whether the speech was directed to an adult or a ba (game character 1 speaking foreign language) (game character 2 speaking foreign language) - Even though the participants had no familiarity with the languages or cultures they were listening to, they were able to guess correctly 70% of the time.

In recent years, some linguists have questioned whether the cultures that supposedly did not use child-directed speech were simply using it in ways that were misunderstood by Western researchers.

In some cases, child-directed sp was performed by older siblings rather than parents.

In others, a high infant mortali may have led parents to delay baby talk a bit so as not to get too attached to And in the case of the Kaluli, parents use a high-pitche voice to speak for the infants rather than to them, like, "I'm Or, "I don't like that."

Guiding them on how they should speak in certain situations.

Assuming now that baby talk is indeed instinctive and universal, researchers sough its evolutionary origins by studying groups of our closest living relatives, great apes.

Surprisingly, they foun virtually no trace of baby talk.

Adult apes from gorillas to orangutans to bonobos rarely, if ever, communicate directly with their young.

Since humans are the only speeches with language, this led them to believe that ba specifically evolved to aid in language acquisition.

If it serves some other emotional or social purpose, you'd expect to see some early v of it in other nonverbal primate That doesn't mean it doesn't serve an emotional or social purpose today.

The process of guiding babies into the wonderful world of language is emotionally rewar for adults and children alike.

Our brains release oxytocin, which promotes bonding and makes us feel happy.

And let's not forget the enormous social benefit of being able to laugh at how people talk to their dogs.