I’ve been greatly helped by my wife in thinking through how we speak to our children. Perhaps it is being nitpiky, but we don’t tell our children “good girl” or “good boy” when they obey or do something good. We certainly affirm them with things such as “well done”, “good job”, “that’s great”, “that was good of you”, “sweet boy”, etc. But at the end of the day, neither of them is good, nor am I. I don’t want to reinforce a self-image in them that is unbiblical and reveals no need for the gospel. I think I know what people mean when they say “good boy” or “good girl” but not much gets passed children, and I can only imagine the conversation to be had when we get to the rich young ruler narrative.
In regards to the more negative side of things, what in the world does “naughty” mean? Why not say that the child has disobeyed or is being unkind. All of the things we might use naughty to describe have better, more appropriate, and more biblical words to be identified by (this also gives your children a vocabulary to identify your sin with, which is helpful in the parent’s own sanctification). Let’s call sin sin, and let’s point our children to Christ, who alone is good, and who is the Saviour, not of naughty children, but of sinners.