sounds like the WWII effort to have the coded navaho speakers since there were so few of them. well, there were actually many langs used - and the sad thing is the dude on your radio was either some white dude with an american indian tagging along, or it was an american indian.
not all divisions had them, so sometimes you'd meet up with another one that was unaware of the coded radio deal, see the indian, and shoot him - he don't look white, so I's gonna kill 'em.
people suck.
I'm part cherokee on each side of my family - but you'd never know by looking at me - I'm a white ass mofo.