Sefer Chofetz Chaim chapter 9 halchos 5, 6

Halacha 5: According to the laws of chinuch, educating your children, one has to even make sure from a young age to train them not to speak lashon hara or any other bad talk like cursing or lying. This is extra important for parents to teach their children because the Vilna Gaon says that it is very hard break habits so, especially for speech and character traits fathers should train there children to have positive character traits and refined speech from a young age so that it will be habitual when they grow up and not the opposite, if parents don’t rebuke then children say whatever they want and train them selves to speak lashon hara, lies, and cursing, which is why they continue when they grow up, since it is so hard to break the habit, though not impossible.

 Halacha 6: If someone tells you something you shouldn’t repeat it unless he tells you, it indicates to you that you are allowed to repeat what he said, except for lashon hara, even if he said you can repeat it, of course you can’t. This is based on a gemara in Yoma 4b: “How do you know if someone tells you something you can’t repeat it unless he gives you permission? The pasuk says ‘Hashem spojefrom the Tent of Meeting saying.'” “Saying” means you can repeat it.