I dare to say it's in our mind , I remember I had this period of my life that I didn't stutter like not even hesitation, I even remembered a word that gave my nightmares and I kept repeating it not stop without stuttering or feeling that my lungs were suffocating me , I even remember saying why was I even stuttering , ironically enough I'm almost 30 years old now and I'm still struggle with making a phone call ....I don't know what to make of it