I probably said 'pop' when I was a child. I generally call it by the brand name or what it actually is - lemonade / coke etc. I would never say 'soda' NEVER.
By It's name ,Coke , Pepsi,Mtn Dew I try to not drink much soft drinks with to much high fructose syrup. I lost around 20 to 24 pound after I stoped drinking soft drinks and start drinking more fruit juice with out Hfcs-55 in it. www.eatingwell.com/nutrition_health/nutrition_news_information/is_high_fructose_corn_syrup_bad_for_you
I don't drink carbonated drinks. I really don't use either word much at all. I would probably use the word soda since I don't think I ever called it pop.
Pop or fizzy is normal round here (England). If I'm talking to Americans I call it soda, it saves confusion
Pop is anything carbonated/fizzy eg cola, lemonade etc Soda, we think soda water, sort of that sour tasting stuff that people put with gin/ whisky and stuff.