It certainly does sound too much.
Can you please give a little more detail?
- Do you literally mean EVERY day? 5 days per week? 6? 7?
- What country is it?
- What level(s) and age(s) are the students?
- Is it a language school, evening classes, boarding school or what?
- Where do the vocab lists come from/how are they generated?
- Are the words related to current lessons, topics etc? Or random?
In short, the more detail you can give the more advice you should receive.