Stuttering can be a self fulfilling prophecy
If the parents show their concern over the dysfluencies to the child, or should others mimic and make fun of him/her, the child's awareness of the "problem" will likely be come accentuated.
Disapproval can lead to fear of failure, and fear leads to failure when it comes to making the highly complex fine motor movements of speech.
A life long struggle with dysfluency, now called stuttering may ensue, and like a firestorm may escalate as fear brings failure, and failure brings more fear.
We have a problem! If there is evidence of struggling in the child's attempts to speak, such as blinking eyes or pursed lips or increased oral pressure, the cat is out of the bag and it is time to call in a speech pathologist.
This is not to say that stuttering in every case is caused by peoples response to a child’s dysfluencies. There are many other causes of stuttering, but this is one pitfall that can and should be avoided.