Who is teaching him??

Owen has a new saying, not sure that I want to put it in the cute category.
Let me preface this by saying he had a bit of a diaper rash a couple weeks ago.
I started to notice he was trying to tell me something hurt. I fianlly caught that he was saying "balls hurt". Who the hell is telling him that they can even be called balls? He is fixated on balls in general and is always chasing one around with a hockey stick. So, did he come up with this on his own or does someone around him refer to them as "balls" and he picked up on it??
Kinda cracks me up, only because he is a cute 2 year old.