Some people utter a singsong baby talk to their beloved pets, as well as to their own or others’ babies. However, pet- and infant-directed baby talk appear to be different acoustic animals, so to speak.
Mothers talking to their babies speak in a distinctive high pitch, exaggerate the emotional quality of their voices, and draw out the pronunciation of vowels. Dog and cat owners also use a high pitch and amplify emotional intonations when talking to their pets, but they don’t stretch out vowel sounds, according to a report in the May 24 Science.
This finding adds weight to the theory that people, and mothers in particular, intuitively use a type of baby talk with infants that imparts lessons in how to speak or at least understand a native language, propose psychologist Denis Burnham of the University of Western Sydney in Australia and his colleagues.
To gather data for the study, the researchers analyzed tape recordings of 12 mothers in their homes as they talked on separate occasions to their 6-month-old infants, to their pet dog or cat, or to another adult. The researchers ensured they would obtain sufficient information on the moms’ vowel pronunciation by supplying the mothers with three toys–a sheep, a shoe, and a shark–that were then referred to during each recorded encounter. Mothers employed none of the acoustic signatures of baby talk while talking to another adult.