In the military I knew most of the flags of the world. I also knew all the Navy flags and what they meant. Oscar is man overboard. Echo is altering my course to starboard. And on like that. I could read and sent morse including by light. I could send semaphore by flags, but my brain is wired so that it was difficult for me to read it. Left/Right brain thing I guess.
I regret to say that I have forgotten most of that now. But when I was a kid, I really had it down pat. It was required, but it became a hobby for me. I enjoyed it.
This woman has obviously lived a very narrow and sheltered life.