I grew up in Massachusetts, and carbonated drinks were generically referred to as "tonic", though if you said "soda", people usually (though not always) knew what you meant. Somehow we managed not to confuse this with "tonic water", the quinine-derived stuff commonly mixed with gin (talk about marrying two vile flavors together... blech!).
Re: Re: I refer to a non-specified carbonated beverage as a: