> I think we should all speak one language (preferably, the one we're speaking now).

Gods no. You'll have to pry my other two languages from my cold, dead tongue. Just the ability to have private conversations in public feels like a superpower. The amazing puns you can make up is also a huge benefit - I can amuse myself all the time.

Plus, you know, cultural diversity, accessing millennia of literature and history etc. But that's the boring stuff /s