Just interested, what's the explicit purpose of your post? I've randomly browsed many articles on LW and haven't so far stumbled upon those posts so I don't think it should be the reason not to post it again. I think it's a sign of a healthy community if some important things get posted again and I don't know why we should prevent it from happening.
How do you expect anyone to contribute if you actively discourage them from doing so? There have been over 2000 articles posted here, I bet you can find something similar that's been posted here of almost anything. I guess it's stems from the slightly unpleasant feeling that people get when they get across something they've already experienced. It's probably something egotistical in nature, at least for me it feels slightly like you're not a part of some elite club anymore, roughly speaking. But in this case you should probably ignore your feelings because I think other things are more important, like making it possible that more people have the chance to be a meaningful member of the community.
Sure, if you began to rationalize this you could say that this is tending the garden, but the implication seems to be that there's nothing wrong with the post itself other than the fact that it's been posted before. Garden can't have many versions of the same plant? It's better that the Discussion section here is not treated like some holy scripture where you have to carefully plan what to put in there (that's Main) and instead treated more like a real world discussion where discussions happen naturally and then they die out and happen again some time later.
If it is important, then it is good to link to previous discussion. In this case, the community repeatedly decided that it was not important. (Edit: no it hasn't, only condemning quick duplicates.)
Okay. You could at least say why it's not important.
(Edit: quick duplicates? it's been 1½ years since the last time it was posted. Edit2. Oops, now realized what you meant by that)
People can read the archives if they want to. Even better they can read just the high karma parts of the archives.
As the claim is for foreign languages in general, not Latin specifically, Latin of the hirsute and sharp-toothed variety works just as well. :D
How late in life would you need to learn that language for it not to hijack your native thinking processes? I was raised speaking Spanish, but by now I can basically think in English with no effort.
Are the people of East Africa -- who are very multilingual, often speaking 5 or 7 languages -- more peaceable than Americans? Are they especially more rational and peaceable when talking in a language that is not their mother tongue (and so probably talking with members of other linguistic groups).
I don't know, but given that we're comparing between one of the poorest regions of the world and one of the richest, I'd expect controlling for all the confounders to be a nightmare. No one's claiming this to be the sole determinant of rationality, after all, much less peaceableness.
http://mappingignorance.org/2014/02/03/mandela-was-right-the-foreign-language-effect/
Summary: Across the board, people are less prone to cognitive bias in a non-native language.
Conclusion: If all important discourse was conducted in Latin, or any other language native to no one, people would make better decisions.
Corollary: All the attempts to make a constructed "scientific language" actually could have worked relatively well, for reasons entirely unconnected to the painstaking scientific structure of the languages.