We use English when we teach the grammar (consonants and vowels) especially for lower level classes, but as the class goes on, we use less English. In Advanced class, most of lessons are done in Korean.
All adult classes have their own text book and lesson plans for the whole year. We review the previous lessons from time to time, but don’t repeat the lesson for new students. Teachers will help new students to get through before, during and after classes.
It varies but maximum number per class is 18.