In the US, there are dialectical difference for what this carbonated drink is called. Generally, in the south-eastern US, they say "coke" as a generic term to mean any carbonated soft drink (Coca-Coal, Pepsi, Fanta, 7-up, etc). In the south-west and north-east US, they say "soda", and in the northern half of the US they say "pop". All of these include all sweet fizzy beverages (including orange, or lemon-lime, or cola flavored) not just brown ones. Technically, "cola" is a sugary, carbonated drink, that is usually brown in color, and often has caffeine, and exampels would be Coke and Pepsi brands. This is more accurate, but it is less commonly spoken. In a restaurant you could say "I'll have a large cola" and they will bring you either Coke or Pepsi brand cola, depending on which one the restaurant sells. If you say "I'll have a soda/pop/coke", depending on what part of the country you're in, this will bean any of the soft drinks, so the waitress will ask you "what kind?" to find out which specific one you want. Here is a cool map of the US that shows what it is called where: http://popvssoda.com:2998/countystats/total-county.html

It depends on which country you are in! In the UK I think "coke" is most common. In the US I believe "cola" is more common. In Thailand it's "cola" too.

we don't use cola here in the U.S. but depending on where you are. you can use coke, or Pop.