It’s best to stay away from marijuana. If you do use it, use it at night but don’t get into the habit of using it during the day like another commenter said he has. It isn’t legal to drive under the influence and it isn’t worth the consequences. In all likelihood it doesn’t help stuttering but anecdotally it can, so it’s something you would have to try but it isn’t a guarantee (when I hang with my friends we smoke marijuana but I never notice my speech is even remotely bad or close to being noticeably deficient when I do smoke so it doesn’t make mine worse to the least). But please don’t start smoking during the day because you think it will help your speech. Try different methods like SpeechAnxiety.com or even an SLP if you haven’t tried yet. I personally have no issue with drugs so try them at your peril but don’t think it will help ur speech with certainty just try it out without getting hooked and creating a seriously worse problem potentially ya know haha. Anyways I don’t mean to admonish you just opinion. Good luck! :)