This is a very interesting post. I agree with the concept of maintaining as many languages as we can, for the simple reason that there are certain things that are only understood if you read into it as the culture intended.
I have gained an appreciation of this by reading the holy books in their original tongues, then going to scholars that are fluent in those languags in order to have them explain the different concepts of the books. So many things got lost in translation when someone translated the books of the Bible or the Qu'ran into English from their original tongues.
There is a local indigenous language in northern Mexico, no more than a few hundred speakers. In English, we would ask someone where someone is born. In that language, the correct question, roughly translated, would be "where did they bury your placenta?" The concept speaks for itself; the person when they are born, are attached to a placenta, which is then discarded after birth when the umbilical cord is cut. It even sounds quite poetic in a way.
In southeastern Mexico, likewise, there are many dialects there, though not as endangered as they have anywhere from a few thousand speakers to nearly a million. One way they ask about your feelings is "how is your heart?" instead of "how do you feel," with the expectation that the people are truthful about their feelings and they don't try to conceal their true emotions.
Things like this simply get lost in translation when we simply say "How do you feel?" or "Where were you born?" or a simple "Hi" when you might say, "How is your heart?" or "Where is your placenta buried?" or a simple yet profound phrase from the Scriptures like "Shalom Aleichem" or "Salaam Alaykum"