Private language centers offering English as a Second Language are in high demand in the larger cities of Hanoi and Ho Chi Minh City. Students flock to these schools to increase their employment opportunities. These classes are usually taught by foreign expatriates who are generally paid between 10USD-20USD per hour, depending on both their qualifications and the quality of the school. Lower standards in some of the lower-paying schools have resulted in low-quality teachers (known to the local community as "backpacker teachers") proliferating.