I've had mixed experiences with weed. When actually high, I get quite anxious when talking to people and this kind of makes my stammer worse. I usually smoke in phases; I'll smoke every night for around 2 months and then stop for around two months. I find that my speech is better during my smoking phases; for example, if I smoke tonight then my speech will generally be better tomorrow. It may be related to just thinking about my stammer on deeper level when stoned or the fact that I get a much better sleep when stoned. Alcohol however makes my stammer worse.