What is the best setup for a multilingual site configuration?

I have set up 2 sites with the same content but different languages. I want to send emails to both sites, but the timing of the emails in both languages will not be the same. And the campaings may be slightly different as well.

I thought it may be nice to track everything in one Mautic instance, but there are some problems. I would like the segments to be different in every language, so that the user can choose only the segments that are applicable for their language. I would like some options to do statistics on a per language basis. So I wonder whether there is a way to do a nice separation within the same Mautic instance, or whether it will be better to set up a separate instance for every language.