It's not just annoying to you when you have to remind your child over and over again to return to a task. Just the sound of your voice can be a bigger distraction to a child who is struggling to concentrate. Instead, come up with a couple of basic signals (pointing to what they're supposed to be doing, patting a shoulder when you notice their attention has wavered) that indicate that your child needs to refocus without any disturbing talk. It might sound silly, but speaking from experience, it can really work.