Here are some useful resources to help you to better understand speech and speech therapy.
The free e-book Sometimes I Just Stutter
The Stuttering Foundation YouTube channel (including helpful videos for parents)
The Stuttering Foundation's free brochures
Check out resources from the Stuttering Foundation store, including the following DVDs:
The National Association of Young People who Stutter: A US-based support organization
The following PDFs contain useful advice and tips :