Swear Words

My 8 year old son and I were running errands last weekend.
From the back seat Rowan inquires, “Dad?”
“What buddy.”
“There are two swear words, I wish I could say.”
I replied, “Really? Which ones?”
A short pause later, He said, “The O word and the H word.”
“Hum! Do you mean Hell?”
“No! The other H word.”
“Row, I don’t know another H word.”
“Dad! You know. (sh) (t)”
“What?”
Rowan said it again, “(sh) (t)”
“Shit doesn’t start with H, it is the S word.”
“Dad, you just said shit, oops so did I” giggle giggle
Rowan and I discussed the proper phonetics of if this until he was satisfied it really was the S word.
Then I asked him what the O word was.
Rowan responded, “Dad. You know. Oh Shit!”