Erlang

Erlang is a programming language created to be used in developing scalable real-time systems, such as e-commerce, telecommunication, banking, or other similar applications.

Another use of Erlang can be in developing database applications, or in creating servers for web apps.

Its IDE is easy to install, it's very user-friendly and comes with a simple and clean interface. It doesn't have advanced configurations or theme customizations, but it impresses with its responsiveness to user actions. Yet, the shell's default font text looks quite outdated.

To help users accomodate to its syntax, Erlang provides first-time users a complete documentation section on the official website, where they can find various tutorials and examples of how to use this programming language.

As for its capabilities, Erlang has complex components for network systems, like an HTTP server, a Simple Network Management Protocol, an OAM subsystem, and a distributed database engine.

Overall, Erlang may not be the most known programming language, but its functionalities are used by powerful companies like WhatsApp or Yahoo!, and it's surely worth your try.