My parents are also fairly fluent in English. My mom regularly gets mistaken for my sister on the phone. And my dad faithfully reads “It Pays To Enrich Your Word Power” in Reader’s Digest. SN. Our entire family used to read RD, and I’m not certain, but have a hunch, that all of us read it on the toilet. Both of those facts – that we read it, and where we read it – says something about us, I think. Not sure what though.
They still make systematic errors though. When nervous, my dad uses a** instead of “butt”, which is startling. (But nowadays, I’m not even sure if that’s profanity. They say it on the radio all the time. Times are changing. Scott Adams is right – it’s not profanity anymore unless it’s so vile and vulgar it causes the hearer and their pets to light on fire. Everything else seems to be fair game.) And his “bold” and “bored” sound very alike. He was once telling us about how he was praying for someone and for some reason felt very “borld”. It was amusing at the time.