I stuttered very early in life, and I think to deal with how debilitating it was, I just stopped talking. I'd rather be thought an idiot than be made fun of for stuttering or see the frustration in the other person's face as I tried to talk.  It took years of speech therapy and learning alternate methods of communication before I was able to talk again, and even then I still had my stutter.  My stutter, THEY say, is likely part of the development delay I caused by my mother's drug use while pregnant with me.  While selective mutism was easy to slide into as a coping mechanism, it was very difficult to get out of and not at all conducive to functioning in society. I could easily, even now, backtrack, and had I no obligations I probably would. I kind of wish society would embrace selective mutes like they have introverts. With all the technology available, it is far more feasible than when I was little.