by Marianne English

The "uh" and "um" breaks in natural speech aren't as useless as you might think them to be, at least for children learning the ins and outs of language.

A group of researchers found these breaks in speech, commonly called "disfluencies," may help youngsters pick up what's important in conversation. The team discovered that the ability to pay attention to disfluencies develops at around 2 years of age. For instance, if a parent says, "Come look at thee, uh, hummingbird," the disfluency "thee" and "uh" indicate something novel or important will follow. Such communication helps listeners clarify what the speaker intends.

In a study featured in the journal Developmental Science, 16 toddlers sat on their parents' laps while researchers ran a series of objects, both familiar and new, on a large screen. A voice recording played back statements about the objects with and without using disfluent words. For example, one trial presented a ball and stated, "I see the ball!" while another would repeat something along the lines of "I see thee, uh, ball!"

Since researchers presented both new and familiar objects with and without speech disfluencies, they were able to get a better idea of what was causing the increased attention in children.

They found that children not only looked more frequently at the objects described using disfluencies, but they spent more time looking at the object as well.