A word once spoken can never be recalled

French: Un mot dit ne peut être repris (literally: A spoken word cannot be taken back)
Spanish: Lo dicho, dicho está (literally: What is said is said)
Japanese: 口から出た言葉は取り戻せない (Kuchi kara deta kotoba wa torimodosenai) (literally: Words that leave the mouth cannot be retrieved)

Meaning: Choose your words carefully, for once said they cannot be unsaid.

Origin: Latin proverb reflected in Horace's Epistles; echoed in English literature since the 16th century.