조용히 하세요 means “Please be quiet” or “Keep silent.” It is a polite command used in situations where silence or lowering one’s voice is needed.
Breakdown:
조용히 (joyonghi) → “Quietly”
하세요 (haseyo) → “Please do” (polite request)
Examples:
In a classroom setting:
선생님: 조용히 하세요! 수업을 시작할게요.
Teacher: Please be quiet! The lesson is starting.
In a library:
여기는 도서관이에요. 조용히 하세요.
This is a library. Please be quiet.
At home when someone is sleeping:
아기가 자고 있어요. 조용히 하세요.
The baby is sleeping. Please be quiet.