Younger kids repeat your words exactly, tone included. Talk like you’re being recorded, because in their heads you are.

Children copy the delivery long before they understand the content, which means what you actually pass on is tone: how you speak about other people, how you handle being wrong, what you sound like when you are tired. They will use those exact phrasings later, in rooms you will never see, with your voice attached. None of that gets chosen deliberately at the time.

Pick the one habit of speech you would least like repeated and work on it where they can hear you. Say the generous version out loud on purpose. They are learning the sound of it rather than the argument.