New research has found that stumbles in fact display a positive effect on the toddlers who believe that they are being taught something new and pay more attention.

The researchers conducted the study on three different groups of children, all aged between 18 to 30 months who were then shown different images with a recorded voice describing the picture. The researchers found that when the voice stumbled before describing the image, the kids looked up to the image on more than 70 percent of the times.
However this type of learning was effective only among children over two years of age who were able to string together sentences containing two to four words. The study has been published in the online edition of the journal Developmental Science
“We're not advocating that parents add disfluencies [stumbles and hesitations] to their speech, but I think it's nice for them to know that using these verbal pauses is OK – the 'uhs' and 'ums' are informative”, lead researcher Celeste Kidd said.
Source-Medindia