Noticing the invisible

I just hung up from a phone call, and a few seconds later, thought "wait a minute! That person didn't have an Australian accent?!" When I lived in the United States, I'd notice if someone had a strong regional accent. Now that I've been in Australia for five years, when I run into someone who might have an American or Canadian accent, it doesn't even hit my consciousness until later. My doctor doesn't have an Austalian accent. Her name is Indian, and she's mentioned relatives in the UK, but her accent isn't British either (and I haven't even thought to ask). On my last visit, she used a word or two that had a tiny hint of Australian, but not enough to indicate immersion from birth. There's a guy I met through volunteering who grew up in the same Sydney neighborhood as my wife, but his Australian accent is so thick I frequently have to ask him to repeat himself. My wife's parents spoke Greek, but her accent isn't Greek, it's only mildly Australian.