This kind of title appears once in a while in feeds and in search results about languages (I do search for languages trends).
I want to make my own list. I am not going to suggest a language because they can give you a job, high salary, or because it’s what all the buzz is about. These factors mean nothing.
I am not going to explain why you should learn something about all those languages: you will get it once you study them!
Some languages allow nested functions (or procedures, or subroutines, or whatever you prefer to call them), others don't.
I think those can be useful and I wonder why they aren't embraced by all living programming languages.
Java 8, released in 2014, introduced lambdas and the possibility to write code in a functional style through streams of elements. C++11 standard was published in 2011, and it introduced lambdas too, which altogether with old and new functions in algorithm (e.g. accumulate(), for_each(), count(), transform()) allow for a functional style in C++.
