http://www.stutteringhelp.org/Default.aspx?tabid=151
This document also available in Spanish
Stuttering Foundation of America
If your child has difficulty speaking and tends to hesitate on or repeat certain syllables, words, or phrases, he may have a stuttering problem. But he may simply be going through periods of normal disfluency that most children experience as they learn to speak. This pamphlet will help you understand the difference between stuttering and normal language development.