Erlang is described as 'general-purpose concurrent, garbage-collected programming language and runtime system used to build massively scalable soft real-time systems with requirements on high availability' and is a programming language in the development category. There are more than 25 alternatives to Erlang for a variety of platforms, including Windows, Linux, Mac, BSD and Haiku. The best alternative is Python, which is both free and Open Source. Other great apps like Erlang are Java, PHP, C++ and Go (Programming Language).
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose, powerful programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features.
Ruby is a dynamic, reflective, general purpose object-oriented programming language that combines syntax inspired by Perl with Smalltalk-like features. Ruby originated in Japan during the mid-1990s and was initially developed and designed by Yukihiro "Matz" Matsumoto.
Haskell is an advanced purely-functional programming language. An open-source product of more than twenty years of cutting-edge research, it allows rapid development of robust, concise, correct software.