1. Reading out loud gives you more opportunities to practice speaking fluently, either by using techniques or by not being stressed and having a good flow. 2. When you get in the fluent mode (which you eventually do because reading is easy), you are strengthening neural pathways in the brain that are good, making a stronger habit of being fluent. This weakens the habit of stuttering, which develops when the brain uses a different, faulty neural pathway to program speech. Unfortunately, stuttering is a very self-reinforcing habit, meaning that every stuttering occasion weakens our brains preference for using the fluent mode. Therefore, we have to grind speaking fluently, whenever and wherever we can, as much as humanly possible. It gets easier with time, but we can't afford to be lazy.