Here is the story that Betsy Rohaly Smoot tells in this valuable 414-page resource for World War One students.
. . . American leaders, diplomats, commanders, and forces were not ready for what awaited them “Over There.” Once engaged alongside our French and British allies, the US Army and US Navy had to learn fast—and indeed had much to learn. Both communications security and the art of exploiting it had progressed dramatically since the war began in 1914, making it imperative that the Yanks learn new methods (and develop new mindsets) as fast as possible if they were to contribute to an Allied victory. To their lasting credit, they by and large did exactly that, ending the war in 1918 as junior partners but nonetheless valued members of the coalition team that defeated Germany.