He actually wrote a manual on his method, where it came from, and how it works. I'm not sure if it is still available for download. I got a copy a couple of years ago.
Are you have to do is get past the first lesson, and then it's all language training.
I was a volunteer teacher in Africa from 1988-91.
I would write letter from my village, and it would take one month to get to my family in Canada. They would write a response, and it would take one month to get back to my village. That was just the reality.
Now the village I lived in has a cell phone tower in the middle of it. I haven't been back, but I am willing to bet that a lot has changed.