Guess again.
Everybody West of the Mississippi River most likely. It was something we were raised with ... just like you and soda or "a malted." A soda here would probably get you a scoop of ice cream, carbonated water, and a syrup flavored what ever you wanted. Chocolate, Cherry, even Vanilla .... all great "soda" flavors. We had every flavor under the sun when we were kids. Root Beer, all flavors from orange, berrys, chocolate coke and pepsi ... but the diff flavors were cans as well as bottles called "soda pop" and it got shortened to pop. Sorry AC 1846 ... its cultural ... we even have college graduates and rocket scientists here .......