Original sentence: NOVA is the largest employer of foreign nationals in Japan, employing 7000 foreign workers, 5000 of whom are employed as language instructors.NOVA recruits some 2500 to 2600 teachers to replace those who leave each year
Edited sentence: Large English conversation schools like Nova employ thousands of trained and untrained teachers and are occasionally referred to as 'chain' or 'factory schools'.NOVA is recognized to be the largest employer of foreign nationals in Japan, employing 7000 foreign workers, 5000 of whom are employed as language instructors.NOVA recruits some 2500 to 2600 teachers who leave each year