A team of cognitive scientists at the University of Rochester's Baby Lab conducted a study which shows toddlers actually use their parents' fumbling (referred to technically as speech disfluencies) as a signal to help them learn language more effectively.
For instance, say you're walking through the zoo with your two-year-old and you are trying to teach him animal names. You point to the rhinoceros and say, "Look at the, uh, uh, rhinoceros." It turns out that as you are fumbling for the correct word, you are also sending your child a signal that you are about to teach him something new, so he should pay attention, according to the researchers.Yet as a teenager and later as an adult attending class with a few teachers and professors who employed these "disfluencies" too often made it almost impossible to learn. In high school, it was funny and there was lots of giggling at the teacher's expense. In college, it was funny, too... at first. With one prof, we even kept a daily tally of how many of each he used. It would quite often get into the 600s for a one-hour class (For those of you keeping score, that is upwards of 10 per minute or one every six seconds).
Young kids have a lot of information to process while they listen to an adult speak, including many words that they have never heard before. If a child's brain waits until a new word is spoken and then tries to figure out what it means after the fact, it becomes a much more difficult task and the child is apt to miss what comes next, says Richard Aslin, a professor of brain and cognitive sciences at the University of Rochester and one of the study's authors.
"The more predictions a listener can make about what is being communicated, the more efficiently the listener can understand it," Aslin said.
So there I was in a class on which I spent my hard-earned money, so distracted by this man's inability to speak that I was counting his disfluencies. A lot of people could get past it, it was sheer torture for me. Needless to say, contrary to how it works when you're a toddler, "uhs" and "ums" are not conducive to learning when you're cognizant enough to know that's what you're sitting down to accomplish.
Anyways, in the study, the effect was only meaningful in children two years or older. When kids are between the ages of two and three, they usually are at a stage of development where they can create basic sentences of about two to four words. They also tend to have a vocabulary of a few hundred words. Younger children most likely haven't learned yet that disfluencies tend to precede new or unknown words.
Read more about how the study was conducted by Prof. Aslin, along with Celeste Kidd, a graduate student at the University of Rochester, and Katherine White, a former postdoctoral fellow at Rochester who is now at the University of Waterloo.