As a foreign teacher/worker in Korea, health insurance will be compulsory with your employer paying 50% of the monthly premium. This insurance has proven to be a life saver on several occasions for me. Once I was hospitalized after a motorcycle accident my hospital fees was surprisingly low until I realised that the medical insurance had covered almost 80% of the bill. It will also significantly lower your bill when going to doctors or dentists.
Doctors can almost always speak English fairly well and will even be familiar with fancy medical terms that you yourself might not even now. This is because many of them have been educated in Western countries and had to study from English textbooks. So when going to the doctor, communication is one thing you don’t have to worry about.
Doctors often set up their own practices or work at hospitals. Small hospitals can be found on every street corner. For specialized conditions or for something more serious than the common cold you might need to go to a large hospital. These usually have a variety of specialists and are generally more expensive than their smaller counterparts.