Speech therapist here. I have worked with many clients with stuttering. Some of them with mild to moderate levels of stuttering did improve a lot and started managing their speech rate very well in their routine. While there were some complex cases where the client had severe stuttering including head jerks, prolonged blocks, low self confidence and sometimes psychologically disturbed. I acknowledge that some persons with stuttering might have a hard time in applying the speech therapy exercises. But it's not completely impossible. If you have a good therapist nearby then start your speech therapy sessions as early as you can.