Yes it's a frightening fact, our language is alive and if we blink we will be left behind. But it's a wonderful thing to see when our eyes are open. English is by far the biggest language and, lamentably, the most difficult for others to learn but that is exactly the reason to learn it. Many concepts in science, technology, engineering, obscenities, medicine etc cannot be adequately expressed in other languages.
English has always stolen from other languages (and the other way too) and it has always been a hodge podge of them all. Even mighty Shakespere took liberties, among them spelling his own name in a variety of ways.
The British Empire and later Hollywood and the internet age have reinforced English as the language of business and entertainment. While language diversity is an interesting thing, and many are struggling to preserve it, English is what you need for most activities.
And how do you pin English down? It's like nailing jelly to the wall- we have many languages loosely referred to as English: Liverpool, Edinburgh, Dallas, Boston, Sydney, N'arleans, Johannesburg, Mumbai, Hong Kong, (sorry, there is no Canadian city with an interesting variation) ... We are a family of languages that are sometimes intelligible to each other.
No doubt there are some topics best explored in other languages- music, art, religion, anthropology perhaps. But for modern living we got it goin' on!