DD, just to clarify, it wasn't just that they spoke the Navajo language, it was that they then also made up a word code WITHIN that language. That's why it was impenetrable.

I wish the kids got history in little interesting pieces like that rather than from drab textbooks. Did you know Finns were the ones who made it possible to clear much of our eastern timberlands for farming? Did you know 1/3 of the Continental Army was of Irish descent? Lots of stuff like that about the different contributions of different groups and individuals, that doesn't make it into the mainstream of knowledge.