It's definitely stronger among ourselves - you'd have to catch them chatting with other Newfoundlanders, say at a house party or on the phone. If they still just sounded vaguely Atlantic then that's their natural accent. I, however, don't think it's gone that far yet for people who are raised here. There are some people who only have a thick Newfoundland accent for emphasis, like Oprah speaking ebonics, but even their unguarded, natural accent is still generally strong.
Most of us can do a "talking to mainlanders" accent - we generally learn it in school. It's not perfect, standard Canadian English (our vowels still don't sound quite the same, even when we're consciously trying) but it can fool most people most of the time. And it's ingrained in you. If the linguist from that article was interviewing me, there is absolutely no way he'd hear much of my natural accent unless there were more Newfoundlanders in the room talking. Not sure why that happens - I'm not ashamed of my accent, not even subconsciously, I love it. There are still lots of people, though, including my age and younger, who cannot hide it at all. An acquaintance of ours, Beth, is like that - Ayreonaut couldn't believe how thick her accent was despite being from St. John's.
This kid is a good example. There is no way he's ever faking a mainland accent, ever. He'll never be able to reproduce the cadence or flow of standard CBC talk:
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