From Combat Magazine
JODY CALL : rhythmic chants or rhyming songs intended to coordinate marching tempo, sometimes shortened to JODY; probably derived from labor songs that paced the work and maintained the processing order. These songs, along with country and blues, share the common miseries of ordinary people, featuring the archetypal JODY as villain or rake, who typically wins the soldier's pay and possessions, seduces the serviceman's wife and dog! See CADENCE, HEP, CHANTEY, HOISE. [nb: some revisionists, by ignoring the extensive history of martial music and work songs going back to ancient China and early Rome, are "crediting" segregated Negro troops with the 'invention' of CADENCE calls for the improvement of morale during training in WWII, specifically an impromptu "Sound Off" CADENCE call initiated by PVT Willie Duckworth while marching in the Provisional Training Center of Fort Slocum, New York, in May 1944, and later identified as the "Duckworth Chant" in folklore. It's another insidious myth and pernicious lie perpetrated upon the gullible by self-anointed elitists! The similarity of JODY to every carpetbagger and scalawag argues demonstrably for a 19th Century development, as does the word 'cadence' in early Army songs ("count off the cadence loud and strong"), but even more is the persistence of sea chanteys by sailors laboring at common tasks.]
But the info came from the DoD.
Hum. Now thats saying something isn't it.
And your right they were segregated. As the story illustrates.
I was a classics major at one time and recall reading where ancient Greek armies marched with music. I think I can even recall seeing paintings of slaves (maybe) playing flutes in front of the soldiers.