My stuttering hasn’t been associated with certain beginning letter words as you’ve described but more so with my emotional or psychological state at the time. When I was younger, I often stuttered when I was overly excited. The stuttering was worse then as it is now or at least seemed that way because I didn’t try to hide it at that time. As I got older, I started to stutter more on words that I’ve previously stuttered on before. And with the past few years, I now stutter heavily on words that I know I can’t interchange such as names, places, movies ect. As whole though, I feel more devastated by my stuttering in these past few years more than any other time. Being an adult and not being able to say your name is tough.