I did not fully understand the English language until I underwent an intensive six month course in German at the Defense Language Institute. I do not consider myself an expert as English is a living language that grows and changes every day.
Experts cite all sorts of rules. In my 77 (nearly 78) years, I've learned the most important rule - What was yesterday may not be is today.
Languages evolve. Always have. Always will.
What is ironic is that they progress from complex and beautiful to more simplistic and ugly.
Because there is always a group of people who don't like definitions, and create new ones, which make the old ones insufficient. You end up with grunts and curses and symbols.
Like suddenly "life" doesn't mean "life" anymore. When you take a word that has a fundamental, important and accepted meaning, and then suddenly determine it doesn't mean what the majority of people understand it to mean, you have a problem. Communism, primarily. Totalitarianism, certainly.