Languages

.NET (C#/F#/VB.NET)

Why: VR/AR, Windows, enterprise.

C++

Why: OpenCV, ROS, etc.

Elixir

Why: master/slave.

Go

Why: command-line tooling.

Kotlin (JVM)

Why: Android, JVM.

Python

Why: the major scripting language.

Ruby

Why: a major scripting language.