Reason for English Dominance: Slang?

The scene is a mysterious one, beguiling, thrilling, and, if you didn’t know better, perhaps even a bit menacing. According to the time-enhanced version of the story, it opens on an afternoon in the late fall of 1965, when without warning, a number of identical dark-green vans suddenly appear and sweep out from a parking lot in downtown Madison, Wisconsin. One by one they drive swiftly out onto the city streets. At first they huddle together as a convoy. It takes them only a scant few minutes to reach the outskirts—Madison in the sixties was not very big, a bureaucratic and academic omnium-gatherum of a Midwestern city about half the size of today. There is then a brief halt, some cursory consultation of maps, and the cars begin to part ways.