I read a Japanese essay about selective mutism Hanaseru youninatta Masaesan (Ms. Masae gets to be able to speak), written in 1983. The author is Yasunori Ishikawa, a former teacher of elementary school.
The book is characterized by showing teacher's point of view about selective mutism. We can hardly find books or blogs written by teachers. Many Japanese books about selective mutism is written by therapists. Many Japanese blogs about selective mutism is written by people who suffered (or suffer) from selective mutism or their mothers.
The author administered controversial " treatment." He sometimes forced Masae to speak. When she wouldn't speak, he shouted at her or hit her head as hard as he could.
As a teacher, the author seemed to think that he needed to set goals (for instance, speaking in a social setting) and made children achieve them even if they reject that. That's education. But therapists don't think that way. They emphasize acceptance.
The author also tried to conduct comprehensive educational activity to open Masae's heart and recommended her to read books to promote her intellectual development. I think that is estimable.
Index of SM in Japan