Instead of relying on brain training, try to cure your anxiety with meditation, gratitude, laughter, and other similar practices. As your anxiety decreases, you will have less fear. When your anxiety is at zero, your fear will also be at zero. Or Consider taking an online course to effectively address your stuttering without harmful side effects. I stuttered for 28 years, but I was able to fully cure my stuttering. Now, I am more relaxed, happy, always looking for new friends, and have zero social anxiety and fear. I practice meditation, silent laughter, gratitude practice, and some other secret practices to cure my stuttering.