There is no single answer, reason, path. Some of these men had to learn the language in 6-12 months.
Six Who Served
"The day after Pearl Harbor, I was on the living floor of my fraternity house, Beta Sigma Rho, listening to Franklin D. Roosevelt’s broadcast. We were stunned. I had graduated from Columbia in June 1941 but had remained to take my master’s in French. I remember going to class that day. I had a professor of 19th-century French literature and criticism, and he encouraged us to be firm and have resolve, and not to lose our spirits, because our way of life will prevail.
It was obvious to us that we would have to serve in some way or another. The father of one of my fraternity brothers said to me, “You’re a good linguist, you got honors in French. Take Japanese immediately. There will be a desperate need for Americans who know Japanese.”
So I enrolled in an intensive Japanese class in the spring semester. A member of our course was Henry Graff, who later became a professor of history at Columbia. By the time the class ended, we could read and write pretty well, so when military recruiting officers came to Columbia, it was a gold mine for them. The Navy snapped up several of us.
In June 1942 we left on the Trail Blazer from Pennsylvania Station to Chicago. There we boarded the Denver Zephyr and took a bus to Boulder, 34 miles
away, to the Navy Japanese Language School. It was originally located at the University of California at Berkeley, but because of that tragic page in American history where the Japanese were moved inland, the whole school was relocated to the University of Colorado. A member of my Columbia College graduating class transferred from Berkeley — William Theodore de Bary, who later became chair of the Department of East Asian Languages and Cultures and provost of Columbia. We were pretty good at Japanese because of the training we had had at Columbia, so for the first few months of school, we did a minimum of homework while everyone else caught up. We got to go horseback riding and went swimming in the lake. That was fun. We were commissioned in July 1943 as ensigns.
For the first few months we translated Japanese diaries taken from the bodies of soldiers in the Pacific. Here were young men our age who had obviously perished. And the bloodstained pages were indicative of the conditions under which they died. They wrote simple things: the feelings that they had at the time. The human tragedy of war was so stark for us. We couldn’t help but empathize with these gallant people who fought for the things they believed in. But the wrong goals, we felt.
If I hadn’t learned Japanese, I probably would have been drafted and ended up in the infantry."