I took magic mushrooms for the first time with a friend in university. My speech was completely fluent for the duration of the trip. The ease at which I could speak was unbelievable, and I don't have the same effect with alcohol. It just flowed and I didn't obsess about what I was saying or going to say. Really did make me think about a lot of things I believed about my condition. Have a look at Paul Stamets and how he cured his stutter.