I’ve created a userscript that hides posts based on the language set in the badge.

You can change the whitelisted languages by adding them to the whitelist variable. For example, if you only want to see English and German posts, you can change the whitelist to let whitelist = ['en', 'OC', 'de']

Let me know if there are any issues! I haven’t tested it much, but it seems to be working well