Verbseoul.
하다 verb (adj)
조용하다joyonghadato be silent, quiet, still, calm, empty, sedate

To say to be silent, quiet, still, calm, empty, sedate politely in the present tense, use 조용해요 (choh-yohng-hae-yoh). Below is the full conjugation of 조용하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
조용해
choh-yohng-hae
조용해요
choh-yohng-hae-yoh
조용합니다
choh-yohng-hahm-nee-dah
Past
조용했어
choh-yohng-hae-ssuh
조용했어요
choh-yohng-hae-ssuh-yoh
조용했습니다
choh-yohng-hae-sseum-nee-dah
Future
조용할 거야
choh-yohng-hahl- -guh-yah
조용할 거예요
choh-yohng-hahl- -guh-yae-yoh
조용할 겁니다
choh-yohng-hahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
조용하세요
choh-yohng-hah-sae-yoh
Suggestion / Let's Polite (요)
조용해요
choh-yohng-hae-yoh
Question Polite (요)
조용해요?
choh-yohng-hae-yoh-?
Connective “and” — (고)
조용하고
choh-yohng-hah-goh
Conditional “if” — (면)
조용하면
choh-yohng-hah-myuhn
Noun form — (기)
조용함
choh-yohng-hahm