Used to chant cadences silently to myself to keep time as I ran 10ks 2 or 3 times a week. But that was over 40 years ago. Now I'm a retired attorney so I haven't PT'ed in a long time.
U.S. Army! Where you learn to call cadence with soul, in clear, plain English. As God said, it should be. You'd be hard pressed to find a marine, mumbling a cadence in the Army. They'd be regulated to "road guard", right quick! Not a soldier would lose any sleep.