I am happy to join this forum. I am a teacher of English and as well as a director of an English school in Vietnam. I think the ideal size of a class is just about 10 - 15 students because the students should have time to talk, to express and share their ideas with others. If the class with less than 10 students is a little boring, the students feel lonely so they don't want to talk.
Benny
email:
eslschool2007@yahoo.com