I am going to learn German this year. I already have a plan, and a good one, but I don't have the resources I need. The most useful resource is interaction. You don't quite need immersion, to speak a language comfortably, but you do need interaction with people who speak the language. You don't have to order your pizza in another language, and everything else also, but those would be forms of interaction you could use.
Now, the Occulus rift is a virtual reality device. This means it places a real person into a virtual world. But the more useful type of technology is augmented reality. Augmented reality projects virtual things into the real world.
Even better would be a merger of the two. And I think a merger of the two would be something similar to a hologram.
At that point, you could have virtual interaction in 3d space with a real live person in another country.
I think augmented reality is going to get bigger, at least I think it should. But virtual reality needs to be paired with it. Perhaps you can hack the Occulus to do this?