dead men tell no tales
Definition:  people who know secrets cannot reveal them to anyone after they are dead; when people die, they take the secret to their graves
Usage:  he knew that dead men tell no tales, so he decided to lie about the deceased

SEPEDI
Translation:  bahu ga ba anege dinonwane
Proverb: koma re bolla kgororwane khupamarama re hwa nayo

XITSONGA
Translation:  mufi a nga hlamuseli xitori
Proverb: u nga fayi tandza, swihlangi swi langutile

TSHIVENḒA
Translation:  vhanna vho lovhaho a vha anetsheli nganea
Proverb: zwa mbiḓi ndi zwa maramani, zwa thumbuni i fa nazwo