So, I hear two voices, in two languages, none English, all from one person having a conversation with themselves in the kitchen. I wouldn't be doing my job as a mom if I didn't acquire more information.
So I ask "Who's in the kitchen?"
It was William and it was at that moment he realized the conversation he thought he was having in his head was actually out loud. He started to giggle and get embarrassed.
So I said "Welcome to the family, you're officially one of the odd ones."
It was at that moment that he realized others (unnamed) in the house do the same thing and he, at eight years old replied "ahh crap!" and walked away.