Even though this article is on a .com.au site, Business Insider also has a .com site. The author of the article is Christina Sterbenz. Further checking reveals Christina lives in New York, so it starts to make sense that some of the content may not be correct.
If you search the internet for a part of the document, such as "These students spend months, sometimes years, studying for their big moments on the mic.", you'll see the article is being republished across the internet. For Australians the word "memorize" has been changed to "memorise", which is appropriate. But it is easy to change the obvious, but only an Australian editor/journalist would pick the less obvious differences in the language, that we as Australians will read as errors.
As you read the article there's small clues that catch your attention, which makes you suspect this isn't an Australian article. The first is the word "Anglicized". Yes they got "memorise" correct but they've not been thorough. Where the article really tripped me up is when they started talking about how we sound a word. That's when it didn't make sense as how Australians and Americans pronounce some words is different and it then became apparent this was an article that could mislead people.
Perhaps the worst piece of advice is to check the Oxford Online Dictionary. This is something you shouldn't do in Australia. We don't have a free online resource in Australia, but if you do check a word, use the printed Macquarie Dictionary and/or the Australian Oxford Dictionary.
There's some great information in the article which is very useful. However always keep in mind it you're not aware, you don't know what is good advice and what is bad advice. You'll start to absorb some of the bad advice and believe it to be true. That doesn't help you in the long run.
The preferred Australian English spelling.