Tom, do you think that if a stutterer had sudden total amnesia, he or she would cease to stutter? I ask because I surmise that if I have times where I am fluent, then why can't I find a way to ALWAYS be fluent? Doesn't that indicate that I have the capacity to be 100% fluent? Maybe if I forgot about stuttering...it would disappear?
My answer is the following. If you have a total amnesia (where I include semantic memory but also associative memory), you will be like a young child at onset. You have a brain that is prone to abnormally long and frequent jamming or delays of speech initiation. These delays will feel long but just like a mechanical failure in the sense of accidentally hitting a chair because you had a glitch in your motor code for walking. You will not feel any fear or nervousness. And your jamming will probably only be noticeable in very stressful or demanding situations. And you will not have any secondary behaviour. However, over time you will feel the functional handicap and the social reaction. Coupled with your knowledge of what is normal speech and what role you want to play in society as a person, you will start to react to your jam-prone system and develop secondaries. You will add tension to get out what you want to say more quickly. You will also learn to fear certain words and situations. This associative learning will then trigger more stuttering and nervousness.
To sum up, your neurobiology is still there, and the information content that you have lost in amnesia will be filled again with learned behaviour, fears, and beliefs. BUT THEY WILL LIKELY TO BE DIFFERENT TO YOUR ORIGINAL LEARNED BEHAVIOURS, FEARS, AND BELIEFS.
You can be 100% fluent but only if you manager to control your jamming in two respects: (a) you take measures to reduce the neurobiological jamming, such as staying calm in demanding speaking situations, sticking to pauses, shortening your sentences, and so on (b) you take measures to prevent yourself/your brain from launching a reaction to jamming that is counter-productive to speaking fluently.