Baby Talk Is Universal: Even Monkeys Do It

The words in different cultures may be different, but the sounds are the same.

Researchers have found that people from varying cultures can tell when someone using a non-native language is speaking in "baby talk." And baby talk is not limited to humans. A separate new study suggests monkeys use it, too.

Baby talk involves more than just cooing at a cute little face. Mothers use different vocal cues, such as pitch, volume and rate of speech, in different situations, so that a given word can take on varying meaning pertinent to the situation. Warning a baby not to touch an electrical socket takes a different tone than calming them when they're fussy, for example.

These audible cues are actually used in all manners of speech, whether talking to an infant or an adult, and can be an important factor in conveying meaning and intention.

Researchers Greg Bryant and Clark Barrett, of the University of California, Los Angeles, speculated that the relationship between sound and intention is universal and should be understood by everyone, regardless of their native language.

Baby talk vs. adult talk

To test this idea, they recorded native English-speaking mothers as if they were talking to their own child and then as if they were speaking to another adult. Their speech fell into four categories: prohibitive (warning a child not do to something), approval (encouraging a behavior in a child), comfort (calming down a crying baby) and attention (calling a baby when it isn't looking at you).

The researchers then played the recordings to the inhabitants of a village of hunter-horticulturalists, called the Shuar, in Ecuador to see if they could distinguish between the types of speech.

The Shuar spoke no English, lived in a non-industrialized society and were nonliterate. Structurally and grammatically, their native language, also called Shuar, is "as far away form English as you can get," said Bryant.

The results of the study, detailed in the August issue of the journal Psychological Science, showed that the Shuar participants could distinguish between baby talk and adult talk with 73 percent accuracy.

"The average pitch of the baby talk is higher," Bryant said, also noting that the rate of speech of baby talk is generally slower.

The Shuar could also tell which category the mothers' speech fell into, but were better at this when the mothers were using baby talk. The categories are likely easier to distinguish in baby talk because adults speak in more exaggerated ways to infants than they do to other adults, Bryant told LiveScience.

"These results … provide support for the notion that vocal emotional communication manifests itself in similar ways across disparate cultures," Bryant wrote in a prepared statement.

Monkey baby talk

Another study, published in the September issue of the journal Ethology, suggests that humans aren't the only animals that use baby talk.

The results show that female rhesus monkeys, like human mothers, use baby talk, also called "motherese", when they speak to their babies and are trying to get their attention.

"Motherese is a high pitched and musical form of speech, which may be biological in origin," said study author Dario Maestripieri of the University of Chicago.

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Andrea Thompson is an associate editor at Scientific American, where she covers sustainability, energy and the environment. Prior to that, she was a senior writer covering climate science at Climate Central and a reporter and editor at Live Science, where she primarily covered Earth science and the environment. She holds a graduate degree in science health and environmental reporting from New York University, as well as a bachelor of science and and masters of science in atmospheric chemistry from the Georgia Institute of Technology.