The up-and-down pitch of baby talk seems to help infants identify individual words more easily than monotonous adult speech does, according to a study conducted in 2005.
Erik D. Thiessen, a psychologist at Carnegie Mellon University, played voice recordings to 7-month-olds. All recordings contained the same nonsense mutterings, but some mimicked the singsong rhythm of baby talk—known to spark infants' interest—while others sounded flat.
Infants distinguished real words from meaningless syllables more successfully when they first heard baby-talk sentences rather than monotone speech. Researchers measured babies' recognition of words by the length of time they listened.
But don't get carried away, Mom and Dad. Past research suggests cutesy conversation with schoolchildren can hinder the learning of advanced vocabulary. Thiessen's study shows only the benefit of baby talk early on. An infant is constantly learning, even when the only word out of his mouth is "Waaah!"