The study, by University of California researchers, has found that the relationships between sounds and intentions are universal, and thus, understood by anyone regardless of the language they speak.
To test their hypothesis, the researchers focussed on baby talk or "infant-directed speech," wherein most adults convey their emotions and intentions to infants, regardless of the language they speak.
For example, people raise their voices to elicit the infant's attention and talk at a much slower rate to communicate effectively.
To assess their theory, Greg Bryant and Clark Barrett recorded native English-speaking mothers as if they were talking to their own child and then as if they were speaking to an adult. The speech varied across four categories: prohibitive, approval, comfort, and attention.
Then, they played the recordings to habitants of a Shuar (South American hunter-horticulturalists) village in Ecuador to see if the participants could discriminate between infant-directed (ID) and adult-directed (AD) speech, and whether they could tell the difference between the categories in both types of speech.
The results showed that the Shuar participants were able to distinguish ID speech from AD speech with 73 percent accuracy. They were also able to tell which category (e.g. prohibitive, approval, etc.) the English-speaking mothers used, but they were better at this when the mothers used baby talk.
This is the first study to show that adult listeners in an indigenous, nonindustrialized, and nonliterate culture can easily tell the difference between baby talk and normal adult directed speech.
"These results also provide support for the notion that vocal emotional communication manifests itself in similar ways across disparate cultures," writes Bryant.
He adds that future research might focus on how infants respond behaviourally when listening to infant-directed speech in a different language.
The study is published in the August issue of Psychological Science, published by the Association for Psychological Science.