I think my 10 year old son stopped being a carefree little kid at age 5. It wasn't just that he had an adult like vocabulary, it was something more. He took things in and really thought about things, difficult things that other kids didn't have to deal with.
He notices that most kids his age have a different sense of humor and he says they laugh over the stupidest things. They don't get his jokes, but older kids and adults usually do.
He always seemed to have more common sense than his adult half siblings. He once told me that with pain comes common sense and this is how he remembered that Thomas Paine wrote Common Sense.
My son is more of an extrovert than I am and uses humor to deal with things, using sarcasm and irony in his humor along with physical humor and wordplay. For example, the day we went to vote, my husband told our son before we left "No politicking" because a few years ago my son used to try to get me to change my vote when he didn't agree with the person I planned to vote for. As soon as my husband said this, my son immediately looked at me, grinning, and said something like "Well I am going to do some "poly-ticcing" and pretended to do a flapping hands kind of thing along with a strange eye blinking thing. He did not do this in public. He just likes to tease me sometimes. But there are times when I wonder if we really do need professional help.
