Jax has been saying this a lot lately.
Obviously it's my fault.
I've tried to cure him of it, though. I really have. I've been very conscious about not using the word around him, choosing the irritating "shoot!" instead, and still he says, "Shit!"
Then, my parents reported that while at their house thie weekend, he ran outside and loudly declared, "Oh, Shit!"
Big Daddy did his best to correct him, to no avail.
Today he said it again, for what reason I'm not sure, but I quickly knocked on his head, got down on his level and said, "No, Jaxie. Don't say shit. It's naughty. Not nice. No, no,no."
After which he knocked me on my head and yelled, "No Shit!!!"