It seems you're looking for a language/runtime that's 'extremely popular' and has very useful runtime features like 'speed, concurrency & parallelism'? This co

It seems you're looking for a language/runtime that's 'extremely popular' and has very useful runtime features like 'speed, concurrency & parallelism'? This constrains the space quite a bit. Languages significantly less popular than Python are excluded by definition [1]; languages subscribing to very opinionated design decisions or too low-level (like C) are also excluded by definition. This only leaves Java, C++, Python itself, and Javascript. If you run Python on a JIT runtime like PyPy [2], you'll probably achieve significant speedup. Erlang, Elixir, Scala, Clojure, languages that also have good approaches towards concurrency are not very popular in the greater scheme of things. [1] the TIOBE index is an imperfect measure of popularity, but let's use it here -- http://www.tiobe.com/tiobe_index http://www.tiobe.com/tiobe_index [2] http://speed.pypy.org/ http://speed.pypy.org/