I’m not entirely clear on what you might want him to repeat to you; it isn’t too often that we ask young children to repeat exactly something we say to them. Whatever the nature of the repetition, my guess is that what you might be saying is long and complex and that he just “tunes you out,” knowing he can’t repeat it. Try to break into small units anything you want him to repeat and see if that helps.
With regard to his not knowing why he has a toy taken away or is in time-out, I would simply give the reason one time. If he protests that he is innocent or maintains that he doesn’t know why he’s being disciplined, just say, “Think about it while you’re in time-out, and I think you’ll understand.”
Remember to speak to him slowly and distinctly. That may also help his comprehension.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.