I was wondering if it was really useful to be putting Nathan in time-outs for his bad behavior (hitting and scratching and screeching at his sisters), but I figured since he stays in the time-out, he must understand it to a certain extent. I might know better what to do and how to discipline my children if I read a parenting book, but I gave up on that when Emma was about 4 months old (that explains why my children act like they do, I'm parenting on the fly).
When he looked at me this afternoon and very sternly (and loudly) said to me, "Mommy, get in da tair!" I realized that yes, he does understand time-outs, and boy does he know how to administer them! I got right into that chair. (not really)