[broadbear]

There are a lot of factors here. Some communities fiercely protect their local tongue. Take Brittany in France for example. They still teach their native language, completely distinct from French, in public schools. This is how long after French has been the official language of France? Additionally, some countries in Europe, such as the Netherlands, have high rates of multilingualism. It is supposedly easier when you are born into it. This enables you to speak the administrative languages fluently while still speaking a native language at home only a few million people on the planet still speak. Loyalty to one's culture can have a lot to do with sustainability of a language. To an outsider, it may seem futile to learn a language like Italian for any kind of practical reason. To an Italian, to abandon their language would be sacrilege.

Globalism may be weakening some languages in the near term as it may make sense for people around the world to learn English or even Chinese, and maybe a few other languages. However, imagine if translation technology became advanced enough to conduct a normal conversation with each party speaking a different language. We might even hold on to that mysterious 4th official language in Switzerland (Romansh) after that. There are plenty of people who would love to go back to their hometown and speak nothing other than the language their parents taught them.