Thanks. Elixir looks interesting. I'm apprehensive about the "runs on Erlang" part though (wary of compiles-to or runs-on languages, unless the "to" or "on" is C).
Actually Elixir and Erlang are totally interoperable with zero overhead. They both compile to BEAM virtual machine code. That "runs on Erlang" part is a selling point IMO.
You should become skeptical of languages that compile to C. I can't get into the details because I don't know them very well, but take a look a pcwalton's comment history for a fairly technical discussion of why it makes a poor compilation target.