Yes, FOREX volume involves an exchange of one currency for another.
Do you recall how much real money George Soros had at his disposal when he wacked the British Pound [not a rhetorical question, but I don't believe that it was all that much]?
I don't know how much he had. Once he started attacking the Pound peg, other speculators joined the attack. The important question was how much money did the British have to defend the peg. Because our currency floats, what this example really shows is that the Chinese are more vulnerable to a speculative attack on their currency than we are.
What I was attempting to write was a comment concerning the volumes in FOREX markets differentiating between outright unhedged sales or purchases, and strategies designed to extract small arbitrage type gains or reduce currency risks through simultaneous sales and purchases of in the spot, futures or forward contracts. Aren't derivatives where most of the action is focused?