Professor Burnham says compared with adult-directed speech, baby talk or infant directed speech has more emotion, irrespective of the actual words used.
He says that baby talk, which has also been called motherese or parentese, is the speech that parents, strangers and even older siblings use when they talk to infants.
It has three defining characteristics - higher pitch, greater emotional sound content and more exaggerated vowels.
“It has a higher pitch and more up-and-down patterns which attract infants’ attention. It also has more emotion,” Professor Burnham says.
“The pitch you can measure through acoustic measurement. The emotion is independent to the words being said. We measure it by filtering the speech electronically so that all you can hear are the ups and downs rather than the words and then ask people to rate how much emotion is in the voice. People consistently rate there to be more emotion in infant directed speech than adult directed speech.
“It also has more hyperarticulation which exaggerates the differences between sounds. The most common sounds that are measured are the vowel sounds.
“This exaggeration helps language development. When mothers use more exaggerated vowels in baby talk their babies are better able to distinguish speech sounds.”
While parents may fear that using baby talk will slow their child’s language development this is not proving to be the case.
There is no need to spend time thinking about what we should be talking to our children about to maximise the language experience - it seems the content doesn’t really matter either
Look Who’s Talking
Just like John Travolta in 1989’s Look Who’s Talking we can read little Mikey stock market listings as long as we’re looking him in the face, and using intonation and exaggeration.
The semantic content is not important. It is the physical characteristics of the speech. “Your tummy wummy is really sore” rather than “your stomach is hurting” doesn’t really matter. The important part is that you’re using the infant directed intonation and the exaggerated vowels.
Professor Burnham says parents naturally adjust how they communicate with their baby during their child’s first year to match their developmental level, and as they grow older adults continue to adjust the way they speak as the child’s language knowledge increases.
The parent and infant have a highly developed conversational dance, each responding to the nuances of the other’s speech.
“If parents or whoever is talking to the child is sensitive to the cues the child gives out then that person will use appropriate intonation, emotion, and speech exaggeration because the infant is very good at communicating what they need. And the cues the child gives out changes with the infant’s age,” he says.
“Infant directed speech changes across development. The way you talk to a six month old is different to the way you talk to a 12 month old.
“How mothers talk to their baby is automatically in synch with their baby’s preferences.”
Characteristics of baby talk
Turning again to the three characteristics of baby talk, it differs from other forms of exaggerated speech such as talking to pets and foreigners.
With pets you tend to use exaggerated emotion and pitch, but you don’t have exaggerated vowels and for foreigners you don’t have exaggerated pitch or raised emotion, but you do have exaggerated vowels.
“When you are talking to a pet you are trying to attract attention with pitch characteristics and portray emotion with emotional sounds in the speech but you’re not trying to teach the pet to talk because you’re not exaggerating vowels,” says Professor Burnham.
“When talking to a foreigner you’re not showing emotion and not playing with the pitch to attract attention but you are trying to teach them the structure of the English language by exaggerating the vowels.
“In the exaggeration of the vowels different languages have different vowel spaces so you exaggerate the vowels within the particular language you’re speaking.
“If a mother is bilingual she would use one set of vowels specifically for English and another for Spanish. It seems vowel hyper articulation seems to be focused towards teaching the vowels of the language. It’s a language teaching device.”