"I remember my mother, who was a teen during the war, speaking of German and Italian POW's working on the farms in the area where she grew up. She said the word was that they were captured in North Africa for the most part, and almost none of them spoke any English."

That is true. There were huge numbers of Germans and Italians captured in North Africa, and it was easier to send them back to the US in empty boats (no shortage of those) than it was to bring in all the food and supplies that would be necessary to sustain them in POW camps located in North Africa. I guess had I been a German POW, I would have far rather sat out the war in some Texas POW camp doing menial labor than being on the eastern front fighting Russians. On the whole, the German POWs were a docile lot, they knew they had it good here, far better than Allied POWs in German camps. There were always some die-hard Nazi troublemakers in the US POW camps, but they were kept segregated from the average Feldgrau grunts who weren't really Nazis. Most of the US POW camps were located in relatively remote areas so there weren't any nearby larger cities they could easily run to and hide if they escaped.