Why do you think many languages can coexist peacefully in some countries and not in others? Please help

Many languages can coexist in some countries because they are united by religion, or the countries function as federations, while in other countries they don't coexist because of cultural differences, but also because of artificially set boundaries.

Explanation:

The language is one of the primary cultural traits. Weirdly enough, even though seemingly harmful, it can be a cause of conflict, though usually based on other factors as well. We can see situations all over the world where there are positive examples wherein one country there are numerous languages spoken and there aren't problems, while in others it is the total opposite.

The countries where numerous languages coexist are usually countries that are united by a religious or political ideology, or they function as federations. Such examples are the USA, Russia, UK, Canada... On the other hand, in the countries where people that speak different languages have different religious beliefs, as well as different political views, have a lot of problems, with people that speak differently often exhibiting intolerance and violence toward each other. Such examples are Nigeria, Mali, DR Congo...