I see someone has actually mapped out the geographic differences between how people refer to soft drinks. (Click here to see larger map)
We live on the edge of the St. Louis centered Soda island. To our north and east in our state lies the land of Pop. I noticed this difference in terms while living in northwest Illinois, but I must admit it never occurred to me while living in Chicago. And how odd is it soft drinks are just called “Cokes” in the Deep South and Texas? During what little time I’ve spent there I guess I assumed anyone referring to a coke probably meant a Coca-Cola.