A lot of people ask me, what is the difference between the standard polite form and the deferential polite form in Korean?  The answer to that is that the deferential polite form uses a higher level of politeness than the standard polite form.  While both the standard and the deferential forms are polite, you would use them in slightly different situations.

For example, you’d use the standard polite form with a co-worker you’ve known for a long time.  Co-workers who have worked with each other ten years or longer still use the polite form at work, because it’s more professional that way.  Outside of work people tend to drop the standard polite form and replace it with the casual form.

You’d probably use the deferential polite form with your boss.  Since Korean society is run on showing respect to those in authority, you want to use the utmost polite speech, which happens to be the deferential polite form.  Out of politeness the boss would probably use the standard polite form to his subordinates, but it really depends on the boss.  Some bosses may drop the polite forms altogether and use the casual form instead.  However, that doesn’t mean you can use the casual form with your boss.

Usually the ending for the standard polite form ends in yo (요).  For example the verb ‘to go’ in the standard polite form would be kayo (가요).  The deferential polite form endings end in minda (ㅂ니다).  So the verb ‘to go’ in the deferential form would be (갑니다).

The general rule of thumb is that the more intimately you know someone, the more appropriate it is to use the standard polite form.  Sometimes a stranger may say to you, malsum jom nachuseyo (말씀 좀 낮추세요).  This means, ‘lower your speech level.’  It’s just another way of someone giving you permission to use the standard polite form.  If you’re still confused about when to use the polite forms, just practice on a case by case basis and see how it goes!