"But what's mind-bending about it is that it doesn't exist in any other language a beginner is likely to have used." This is true about killer features in any

"But what's mind-bending about it is that it doesn't exist in any other language a beginner is likely to have used." This is true about killer features in any language that is above the 'average' on the power spectrum ( http://www.paulgraham.com/avg.html http://www.paulgraham.com/avg.html ). In fact, even beyond beginners, I see resumes for people all the time with 20+ years who have only used Java/Python/C/C++. If you are evaluating languages for power or expressiveness, not just tooling/libraries/domain integrations, you're going to have longer ramp up time on average, regardless of the seniority of the developer, because you're by definition looking for features that aren't average (and therefore not mainstream).