bollix
The last one is least readable IMHO. It's like a regexp. It's the most ambiguous and has the most potential for errors also.
It's hard to typo "function" and have a program still compile/run. It's a lot easier to typo "fn" and still have the program compile/run. Smaller tokens mean more potential errors.
That's like asking an author if he writes using the alphabet or ascii.
Programming language debates are like asking Charles Dickens why he wrote in English rather than Russian. Would his books have been any different in Russian? No - it's irrelevant.
So much of this is down to fashion. Are programmers really bound by their typing speed? No.
The only real thing that matters with a language is "can I run this on hardware X", and "How fast does it run / how much memory". Syntax is utterly irrelevant (Unless you're into fashion).
Lisp is just basic with a different syntax...
I'm sure a lot of it does have to do with conditions though. If you have to wash the eggs anyway, you can keep them in factory conditions, and wash off all the shit. If you're not allowed to wash the eggs, then you tend to be a bit more careful, and keep them in better conditions.
UK: It's illegal to sell washed eggs
US: It's illegal to sell unwashed Eggs
Spoiler: In the UK, we keep eggs outside the fridge, and with the natural protection on the eggs (Removed when washed), they tend to keep for weeks. In the US, they tend to keep eggs in the fridge.
Also a lot to do with how the chickens are kept. If you're not allowed to wash eggs (UK), it's more likely the chickens will be kept in sanitary, good conditions.OTOH, It's cheaper for the producer to keep chickens in worse conditions, wash the eggs removing the protection and make consumers keep eggs in the fridge!
More often than not, it's just about who knows who, back room dealings and favours.
Imagine how much more productive we could be if we stopped reimplementing the wheel every time a new fashion comes around...