Hi A.,
I am a speech-language pathologist, and did a lot of extra work in the area of stuttering when I worked in P.I.S.D., and have continued with my private practice.
Stuttering presents itself in many ways. There are the repetitions - which can occur as phrases, words, syllables, and truly fragmented parts of words. Each would indicate a somewhat different level of stuttering. There is also the prolongation. Since this is never a part of typical speech and language development, you might want to consider contacting a speech-language pathologist. Finally there is the block (air seems trapped in the voice box/throat). This too, is never a part of the typical developmental pattern. Again, I would strongly suggest you contact a speech-language pathologist.
The secondary characteristics, previously mentioned, are often movements children do to try to get their words out fluently. There is a short period of time when the nervous system is sort of "tricked," so it works (i.e. blink my eyes hard and then my words come out smoother) - but just for a short time. Then further stimulation is required to again trick the nervous system. Therefore, I would strongly suggest you not touch your child's arm to stimulate slower speech. Any tactile cue could easily mimic that tricked nervous system effect, and would eventually require a stronger stimulus.
Please consider seeking assistance for your son. Every bit of research points to early intervention. There are many opportunities in this area. UTD/Callier Center even offers a special camp for children who stutter.
Finally, if your child has a rough time getting something out - don't be afraid to acknowledge it. You could easily say, "That seemed tough - but you worked hard and got it out. I'm glad you told me about......" I have spent many hours with the NSA (National Stuttering Association), and what I have heard many adults say is that they thought their stuttering was such a bad thing because their parents pretended it wasn't happening and ignored it. That led the (then) child to feel terrible. I am certain you would not want that for your child.
For more information, you may want to contact the Stuttering Federation of America. They have wonderful resources -- booklets that are only about $5.00. There is one titled something like, "I Think My Preschooler Is Stuttering." They truly offer a wealth of information. The National Stuttering Association also offers quality information.
All the best,
S.
www.startherapyprograms.com