I also taught English in Japan, though to adults rather than high schoolers. My experience teaching in Japan was also in large classes, where students were fearful to speak, afraid they would make an error. For all the hours spent in school and in the workplace, Japanese spoke the language poorly. The same could be said for Thais. Every child spends 3 hours or so a week of classes studying English, but compared to Cambodians, have not made the kind of progress with oral English that their hours of classes would suggest they should have done.