The Importance of "Motherese"

It just so happens that motherese is in many ways ideally suited to stimulate young babies' sense of hearing. Its unhurried cadence is easier for babies to follow, since as we've seen, their nervous systems process auditory information at least twice as slowly as adults. Its louder, more direct style helps babies distinguish it from background sounds and overcomes the fact that their hearing is much less sensitive than adults'. Its simpler words and highly intonated structure—with wide swings in pitch and loudness that enhance the contrast between sequential syllables—make it much easier for babies to distinguish individual parts of speech. And finally, its high pitch corresponds to babies' most sensitive frequency range from the age of about three months onward. In many ways, then, motherese is an optimal auditory stimulus for babies, especially after the immediate newborn period, and it is particularly good for them as they begin to acquire the basics of their native language.

Mothers are not the only ones who speak in "motherese." Fathers, older siblings, and others also tend to talk to infants and small children in this special "baby talk" that my colleague found so objectionable. The same speech pattern has also been observed among infant caregivers across many different cultures. It's hard to say whether we use this speech purely instinctively or because we learned it when we ourselves were children. But whatever the reason parents begin speaking to their babies in motherese, the reason they continue to do so is because the babies respond better to it than to normal speech. For instance, four-month-old babies given a choice between listening to recordings of a strange woman speaking in motherese or in regular adult speech preferred the former, judging by the number of times they turned their heads to activate each recording. The earliest that babies have been shown to be capable of recognizing motherese is about five weeks of age. when they will suck more to hear recordings of their mothers speaking in a highly inflected voice than in a flat monotone.

The preference for motherese probably begins forming in the womb, where the intonation and pitch of the mother's voice are transmitted more faithfully than her specific speech sounds. The preference is then soundly reinforced after birth, since this mode of speech is inevitably accompanied by lots of affection and attention. Given the emotional reinforcement and the auditory features that make it so optimally stimulating to their hearing, motherese is one of the most potent forms of stimulation a young baby receives.

Babies prefer it when mothers speak in a highly- intonated cadence with slow emphasis on syllables highly repeated. This preference may begin in the womb, when such sounds are the only parts of the mother's speech to reach the fetus.