Hi,  I am interested in your post.  There is an interesting paper by Prof. Eric Jackson (NYU), “Adults who stutter do not stutter during private speech”, Journal of Fluency Disorders 70(2021) p. 105878.  In his study, he convinced people who stutter that their speech would not be heard. Under those conditions, all of his 24 subjects were completely fluent.    So my question to you is:  if you can find a place where you really know that you are completely alone, if you then take out a book and start reading aloud, are you fluent?    Irrespective of what your answer is, best of luck to you going forward! What research I've read suggests that each PWS develops their own problematic list of initial sounds and words. Maybe your difficulty with s and st is common or not-so-common (I don't know) but it isn't at all unusual for stutterers to have their own list of bad-boys. If you are interested, there is a long discussion of this in the "stuttering bible", the book "A handbook on stuttering, 7th Edition" by Bloodstein et al. It's an expensive book, but your library might have it.