Hi guys
I would propose you to add tags filtering based on language filter and with Joomla tags system so being able to use Joomla filter tags option for different languages too. You can set up menus and make them work with EB, ES etc for better structural navigation for sites.
Similar now working for Joomla 3.9 see this Github implementation see code here..
https://github.com/joomla/joomla-cms/pull/19509