Hi, your experiences are very common. PWS are often much more fluent when alone. This was one of the first findings of stuttering research going back to the 1930's, and it has been confirmed in multiple studies. It is also common to have particular words that are fluency-problematic. I highly recommend the book, the "bible" of stuttering research: A Handbook on Stuttering, 7th Edition by Bloodstein, Ratner and Brundage. It is readable and comprehensive (and about $165, but maybe your library has a copy). There is a well-known theory about the cause of stuttering, the Anticipatory Struggle Hypothesis, which posits that it is the fear of stuttering that leads to stuttering, which the book covers in detail. But there is also research, covered in the book Neural Control of Speech by Frank Guenther of BU, which claims that there are differences in the brain wiring of fluent speakers vs PWS. What I can't reconcile is: if stutterers have some fundamental brain 'miswiring', how does that miswiring magically go away when they speak while alone? Kudos to you for continuing with your medical education with a stutter. I and everyone on this reddit knows how difficult that must be for you.