Hint: School
The answer to this puzzle is:
1. LANGUAGE
2. STUDY
3. RULER
4. CHOIR
5. MATH
6. RANK
7. HOMEWORK
8. CAMPUS
9. DETENTION
10. DESK
11. GRADUATE
12. PAINT
2. STUDY
3. RULER
4. CHOIR
5. MATH
6. RANK
7. HOMEWORK
8. CAMPUS
9. DETENTION
10. DESK
11. GRADUATE
12. PAINT