What about shmiras halashon? Are we guarding our tongues from lashon hara?

Lashon Hara (LH) is a devastating sin, often committed unknowingly due to ignorance of its complex laws. Regular speakers lose their share in Olam Haba (Rambam); it's equivalent to the three cardinal sins and kills three people (Gemara). Constant study of LH laws (Chafetz Chaim) and filling spare time with Torah are crucial defenses. While the formal prohibition applies only to observant Jews, habitually speaking ill of *anyone* (even non-observant) trains the mouth for forbidden LH against observant people, destroying Olam Haba. Therefore, if not speaking Divrei Torah, remain silent and immerse in Torah.