For me when I smoked weed, and admittedly took acid later in college, I learned that stuttering was really in my head, and driven by anxiety. For many people marijuana increases anxiety, but for me it helped me take a deep breath and control myself that much more and over time, stutter and stammer less and less. Admittedly though my stammer can be quite bad at times, like me pausing for a few seconds on a word, sometimes long enough for other people to be slightly put off by it, but by adding little words or phrases that make transitions easy like “you know” or unfortunately “like” it helps. I will say, for the right person weed is absolutely a great tool to help weed out stuttering, pun intended.