RAY: This is a quasi-automotive puzzler, I believe.

TOM: Oh, okay, fine.

RAY: Some years ago my family and I went on a little ski vacation and we spent the first day hitting the slopes, so to speak. I did most of the hitting, with my face. And after that first day we decided to spend the next day in the more familiar and congenial surroundings of the heated pool.
 

TOM: Good idea.
 

RAY: And while we were there, the four of us, another family started walking toward us and my younger son noticed that there were two very cute, blonde-haired teenaged girls walking in front of what I would assume was their parents. And my son studied them for a few moments and as they drew closer, he said to me, they're Australians, you know.
 

TOM: Wow.
 

RAY: And I said, oh, you've met them? He said, oh, no. They're as strange to me as are my textbooks. And I said, oh, so you've overheard them speaking? He said no.

TOM: Never saw them before in my life.

RAY: Never laid eyes on them.

TOM: OK.

RAY: And as luck would have it, they come and sit right down next to us and before they have a chance to utter a word, he leans over and says to them, pretty long way to come from Australia to do a little skiing. And the father says, uh, you're right mate, it sure is.

TOM: Wow.

RAY: And it wasn't the Crocodile Dundee t-shirts that gave them away, either. Now you have all the information you need. And, and I might add, a significant hint. So the question is: How did he know?