“Pop” it is

A brief history of “pop”:

The word soda comes from soda-water (sodium bicarbonate with acid to create fizz). Its original meaning was sodium carbonate, Na2CO3, but has evolved into one of the generic terms for a soft drink.

Pop was introduced later in 1812 by Robert Southey,

A new manufactory of a nectar, between soda-water and ginger-beer, and called pop, because ‘pop goes the cork’ when it is drawn.

Trailing soda and pop in popularity is coke, which has influence in the south likely due to the location of the Coca-Cola plant in Georgia. “I’ll have a coke,” “What kind of coke?”, “Root beer please”.

I think “soft drink” is probably the best term for this stuff, at least the most descriptive of the words.  But “pop” is the official slang term because the standard English of the United States is found in the Midwest.  There’s a southern accent, there’s a northeastern accent, there are border accents, there’s even a Chicago accent, but people on national news broadcasts and most people in movies are considered accent-less.  Their pronunciations are no different from the Midwesterner pronunciations.

So we drink pop.

The "real" people of America call it pop