Great! Thanks @Gargron
Two remarks though:
1. I don't understand why 'Irreversible filtering' (Drop) won't work in public timelines. I can imagine people don't want to look to 'filtered' all the time and now they can't hide those words. Why is that even there? It isn't used for language filtering, so there is no logic here IMO.
2. This is actually a idea. Why not moving the language filters to the 'Filters' section? Language filters are after all filters too.