I think the more serious problem with these homophones is that native English speakers do not know how to use them correctly and then pass on their mistakes to their language exchange partners. I leaned these when I was in the first grade, and yet some people in college still can't get it right. And don't get me started on your vs you're because that ones probably the most embarrassing of them all.

I never get those wrong, and I have a Master's Degree from NYU, but I am not going to pretend to be any sort of grammer or punctuation expert, because I am not. I do hower even at nearly 55 still get pickle, nickel and sandal wrong sometimes. When I see your instead of 'you're ' I do cringe a bit, but it is such a common error.