낮말은 새가 듣고 밤말은 쥐가 듣는다 (Nanmareun saega deutgo bammareun jwiga deunneunda)

Meaning: Be careful what you say; someone is always listening.

Literally: Birds hear daytime words, mice hear nighttime words

Example: “여기서 남 얘기하지 마. 낮말은 새가 듣고 밤말은 쥐가 듣는다.” — Don't gossip here: walls have ears.

Equivalents in English, French, Spanish, Japanese, German, and 6 more languages

English: Walls have ears
French: Les murs ont des oreilles (literally: Walls have ears)
Spanish: Las paredes tienen oídos (literally: Walls have ears)
Japanese: 壁に耳あり (Kabe ni mimi ari) (literally: Walls have ears)
German: Die Wände haben Ohren (literally: The walls have ears)
Portuguese: As paredes têm ouvidos (literally: Walls have ears)
Dutch: De muren hebben oren (literally: Walls have ears)
Polish: Ściany mają uszy (literally: Walls have ears)
Chinese: 隔墙有耳 (Gé qiáng yǒu ěr) (literally: There are ears beyond the wall)
Arabic: للحيطان آذان (Lil-ḥīṭān ādhān) (literally: Walls have ears)
Turkish: Yerin kulağı var (literally: The ground has ears)