En boca cerrada no entran moscas, “flies do not enter a closed mouth.” In a 2023 list of Mexican sayings for business, the magazine Emprendedor explains it: “Significa que es mejor mantenerse callado en ciertas situaciones para evitar problemas o conflictos innecesarios” (It means that it is better to stay quiet in certain situations to avoid unnecessary problems or conflicts).
In a market dialogue in a reading text of the SEP, Mexico’s education ministry, one speaker says: “¡Ya te escuché, chamaco! En boca cerrada no entran moscas” (I heard you, kid! Flies do not enter a closed mouth).