WASHINGTON (AP) -- "Cuuutie piiiie, youuu are sooooo sweeeet."

That may sound syrupy to the adult ear, but to babies it is an important lecture from the infant's most important teacher: Mommy.

Australian researchers who analyzed the sounds mothers make when they talk with adults, with animals and with their babies found that the parents slipped automatically into a different speech pattern for each audience.

For the pets and for the infants, the mothers used roughly the same tone and rhythm, but there was a subtle difference: For baby talk the mothers went into a teaching mode with the vowels elongated and emphasized.

"These results show that the infant- and pet-directed speech are similar and distinctly different from adult-directed speech," the researchers report in the journal Science. Both pets and babies are spoken to in a higher pitch, with a special intonation, rhythm and feeling.

But only with babies did the mothers use "hyperarticulated vowels," the authors said.

"Mothers exaggerate their vowels for their infants, but not for their pets," the study found. This suggests the mothers were instinctively attempting to help the babies talk, but were not expecting the pets to learn any of the language, the authors said.

Researchers Denis Burnham and Christine Kitamura of the University of Western Sydney, Australia, and Ute Vollmer-Conna of the University of New South Wales, conducted the study by putting microphones on 12 mothers and recording their speech as they talked with adults, infants and pets.

Jean Berko Gleason, a Boston University psychologist and speech development researcher, said the findings support other studies that also have shown parents automatically adjust their speech patterns for children.

"When you talk to your cat it may sound like baby talk, but it's really not providing the kinds of information about the way sounds are made as you do when you talk to infants," said Gleason. "Saying the vowels very, very clearly is really specific for speech to infants."

Gleason said that even parents who studiously avoid using "baby talk words" will unconsciously raise the frequency or pitch of their voice when talking with babies. The chirplike speech often used around babies is common in every language studied, she said.

"When parents say ah, ee or oo, they are saying them very clearly so the baby can get the hang of it, but they don't do that for their pets."

Copyright 2002 The Associated Press. All rights reserved.