I have a friend who has lived here for almost 20 years. His English is close to perfect. His understanding of slang and American culture is excellent. There are still things he does not understand about this country.
To be perfectly honest, there are things I don't understand about this country. There are places I can go where citizens as American as I am are markedly different. Their language is different enough that I would have to ask for explanations. Their customs are different from mine.
The place I am leading to has to do with language. In all the examples noted above, language has been a common theme. Without some common ground, it is very difficult to communicate. Even with a shared language, it can be very difficult.
We, as Americans, have foolishly isolated ourselves from the rest of the world. We have bullied our way into having English considered the international language of choice. It is true that in my travels it has never been that hard to find someone who speaks English to help us communicate with those who didn't. It makes me sad to say that I know that if those people came to our country and needed help, it would be far more difficult for them to find that kind of knowledge. The rest of the world puts up with our rudeness because we are relatively wealthy and powerful. Looking at history, we should know that nothing lasts forever.
It should become a priority in this rapidly changing and shrinking world to learn the languages spoken on this planet. We are at a true disadvantage if we do not. If we do not learn to understand other cultures and perspectives, we will be at their mercy.