I’ve always found it quite strange when someone calls it “soda”. Whenever I hear “soda”, I immediately think of “Baking Soda.”
I understand that in much of the Southern US they call it “coke” even if it’s a Dr. Pepper. That’s just odd to me… but I suppose it’s not all that different from using the brand name Kleenex when you want a tissue, or saying “Frigidaire” when referring to a refrigerator. Branding is a powerful force.
What do term do you use? Is it different from the above, and if so, what do you use and why?