I've read many books that refer to treatment for selective mutism. But as far as I know, all of them are for parents, teachers, and professionals, not for current and former sufferers of selective mutism. I don't know why. But I suppose one possible reason is that professionals think selective mutism should be treated by parents, teachers, and professionals, not by themselves. Another reason is that publishers and professionals think many sufferers are young children who can't read difficult books.
Browsing Japanese websites, I sometimes find former sufferers who overcome selective mutism by themselves. Some former sufferers blame current sufferers who don't make enough effort to overcome selective mutism.
I also have had strong interest in how to overcome selective mutism without relying on other people for some reason. I don't know why, but I think Japanese sufferers tend to cope with their disorders by themselves (But at the same time, there are many sufferers who don't take actions to cope with their disorders).
So, I try to write how to overcome selective mutism by myself. But I recommend not trusting in what I write, because I am not a professional. In addition, I don't know whether this method is really effective.
(To be continued)