What Programming Language Do I Use to Code for AR and VR?

I remember it being 1996, flipping to the back of Girl's Life Magazine, to a directory of websites I could visit; it was a short list. After I had exhausted Yahoo Kids and this, I really wasn't sure where else to go. There was still a lot unsafe things for kids at the time and so my access was quite limited. 

Naturally, when a technology is new, content is a bit sparse. It was probably the same with books when the printing press was developed, and the same with TV when that got started.  If you don't think so, look, this TechCrunch article said so, and they, at this moment are more credible than me. 

This has been the most difficult post to write so far, because it required hours of scouring the internet, 403's, bad writing, outdated information, missing information, information written for experts and so on. Oh, and also, to be a real boss at coding for VR/AR requires an understanding of the underlying elements like geometry and objects and even more dense information like this. It's enough to deter the average person, but let's chug on. 

Questions to ask before getting into it, or questions in general... 
What kind of AR/VR do you want to make? Mobile or PC/System based? 
Mobile: Unity (see below) 
PC/System: Unity or Unreal 

​If you're wondering, what's an SDK? Software development kit; set of tools that allow you to build whatever it is you're trying to build. Here's a chart to compare the different ones.  

For Beginners:  
Unity3d. You can do very basic things without any programming knowledge, but as soon as it's a bit more complex, you'll need to know Javascript or C#. Worth noting Unity also has built in support for Oculus 
Unreal Engine: C++ 

For Experienced Programmers: 
ARToolKit (recommended open source) 

Core Languages to Know: 
Javascript, C#, C/C++ 

Good answer to this question on Reddit 

YouTube Tutorials on Basics of Making Games: 
The Making of Google Cardboard Games Ep. 1 - Unity SDK Intro 
Setting Up Google Cardboard Unity SDK and Unity Navigation Plug-in 
Create a Virtual Reality Game in Seven Minutes (Google Cardboard) 
Tutorial: How to Build a Mobile VR Game with Unity (Google Cardboard) 

Official Resources from the Makers Themselves: 
Samsung GearVR
Google Cardboard
Oculus Rift