The reasons why the U.S. military wanted to use the Navajo language as a code were:
It wasn't written down anywhere.
It was tonal.
It was complex.
<h3>Why was the Navajo language used?</h3><h3 />
The United States military were in need of a code that the Japanese would never be able to break and so they turned to the Navajo language for many reasons.
Some of these reasons were that it was a tonal language which was never written down so the Japanese would never see copies that would allow them to decipher the code. The language was also incredibly complex.
Created to unify the 13 colonies, the Articles nevertheless established a largely decentralized government that vested most power in the states and in the national legislature.