Here is a link to Native Languages and their interpretation of the lost tribes of Israel:
Lost Tribes of Israel and Native Americans I have read about the lost tribes and find many different thoughts/theories on the subject - yet it is all very interesting. I would really like to see the show you saw, lcp. What is the name of the documentary?
The Japanese connection is very probable. In the 1920's a cave was discovered in the Grand Canyon. This cave is enormous and contains several different rooms, all filled with artifacts from Asian countries dating back to prior to the great Egyptian Kings. There is a debate on whether or not this discovery was real or an April Fool's joke. It is interesting, though. I will try to find a link to that story.
What I found so interesting about this "Asian cave" discovery is that it ties in with the Hopi Emergence stories and how they traveled on water after the great flood through a canyon with very high walls before they were able to climb up to the Third World. I have got to research that again. Part of the Hopi stories is about a lost brother who has one of the Sacred Tiles of the Hopi and this is believed to be in Tibet -- which is actually directly opposite the "center of the world" in the ancient Hopi pueblos.