We English language teachers could imitate a native speaker, in any of the varieties of English.
It’s possible for everybody. Some people have more abilities to imitate, but everyone can, for sure, and this is what H. D. Brown advised for learners of a second or a foreign language.
This doesn’t mean you become another person: you keep being the same person: the same person but speaking in English, that beautiful language.
The aforementioned author told about a young man who used to imitate with so much practice that he was thought he was a native speaker, over time.
I also know a friend my same age that went to Texas to live there, some twenty-something years ago, and his friends have told me he speaks like a native speaker. He went to the States when he was some 19 or 20 years old, and that being so young also helps, but the author we’re dealing with however kept advising to imitate… and I add to listen to massively, for example to a radio station in the internet.
The picture above shows a piece of Cantabria, a beautiful province of northern Spain, where I have my dad's family roots.