Perhaps. If you think that most people will be in just one of those communities and not care about stuff that’s of general interest to others, then that might make sense. If you think that most people will be in multiple communities, you might try making just one work.
Do you have multiple mail servers? Other systems?
You can configure things such that users can select the language that Discourse uses (e.g., defaults to English, but you can change it in your own profile).