Stuttering is not a social anxiety issue. Yes anxiety can exacerbate a stutter, just like how anxiety can exacerbate pretty much everything. No one knows what causes stuttering outside of brain lesion/insult and physical/neurological sources. Most people who stutter have not suffered brain trauma and were not born with a neurological deficiency/abnormality - thus the cause of most people's stutter is unknown. Please for the love of God do not spread the notion that stuttering is a psychological problem, because it absolutely is not. Social anxiety comes about because of the stutter and how our society views and treats people who stutter. EDIT: As far as speech impediment meaning neurological, I have not read or heard about this. The DSM specifies stuttering as a neurodevelopmental disorder (meaning they have no clue) if stuttering begins in childhood. Adult onset is due to a neurological insult (also called neurogenic stutter). I'm fairly certain "speech impediment" is synonymous with stuttering and is correctly used interchangeably - meaning both describe the behavior of stuttering and not the cause. My training can only speak for clinical psychology, perhaps a speech pathologist could chime in.