home morto non fala

Galician

Literally, “[a] dead man does not speak”. Attested since circa 1750, as the name of an inn.

(idiomatic) dead men tell no tales
- 1867, Alejandro Benisia, El milano de los mares: novela marítima original [in Spanish], page 268:
  El pirata permaneció callado durante el tiempo que el cocinero estuvo hablando; y al concluir de contar el suceso con todos sus pormenores, se llevó con furia la mano derecha á la boca, dándose en ella un fuerte mordisco, hasta hacer brotar la sangre, esclamando:—«Home morto non fala.» En vista de tan incomprensible rasgo de ferocidad, el presidente le amonestó indignado; mas el gallego, sin inmutarse, replicó que trataba de vengar en su mano la generosidad de no haberle dado muerte.
  The pirate stood in silence while the cook was speaking; and when the later ended telling the incident with every little detail, he furiously took his right hand to the mouth, giving it a strong bite till the blood flew out, exclaiming: «Dead men tell no tales.» Because of such an incompressible show of ferocity, the president admonished him with indignation, but the Galician, undaunted, replied that he was trying to avenge in his own hand the generosity of not having killed the cook before.
Synonym: home morto non fai guerra