Mind you, it could have been that Joe was telling the truth, Lighter. I've taken this from my link, just above your post:
>>>>"....Even today, after fifty years, many people have the wrong idea about the use of the Navajo language as a code. While the agility, endurance and courage of the Navajo soldier in the Pacific campaigns are legendary, only a passing notion of the use of Navajo as code is understood. It was mistakenly seen as a simple process of two Navajos talking to each other. On the contrary the major contribution of the Navajo marine was cerebral. The Navajo marines had literally created an alternative Navajo language. They changed around and substituted words. The result was mixed up Navajo. Not even native Navajo speakers tested with the new code talk knew what these Navajo marines were talking about. "That's crazy Navajo," one remarked. In addition, none of the Navajo code was written down. It was all committed to memory! The Navajo Code Talk was born and became one of the most potent weapons used by the United States in the Pacific campaign.
Yet, military intelligence, still skeptical, and demanded a demonstration. Two of the top intelligence officers who were specialists in breaking codes were called in to test the Navajo Code Talk. They couldn't even transcribe the sounds they were hearing much less decipher its meaning. The potency and practicality of the code was firmly established. When the Japanese first heard Navajo code talk, they were totally confused, and it was decades after the war that the source of the code was revealed. The Navajo Code Talk was top secret and retained a classified status until 1968...."<<<<