Different Wave-lengths?

It's been ten years since we moved to Australia, yet I still have difficulties interacting with the locals.
I went to the McDonald's in Gordon with Johnson the other day after picking him up from school in the afternoon. I went to the counter for our orders with a girl. Here were our conversations:

I, "Fruit fizz.". Girl, "Fillet-O-fish?"
I, "Hamburger." Girl, "Apple pie?"

My goodness. What a difference!