NA Foursquare added should work but i can't confirm that. NA JCV will for sure, but to get full Voice Command features you'd need to have Full NA mapping or CA & US at a minimum loaded. You could try to add same version CA as an unlocked map on the mirsoSD separate to your purchased US lower 49 then i'm pretty sure that you'll activate all voice command provided you have the corresponding map specific ASR/SRX files in the ASR folder [even though the CA map itself won't be usable for navigation].
That's very confusing of Garmin in regard to the traffic receivers. I know that some current and recent models like nuvi 150 and related series have traffic receives onboard rather than in the charge lead, but i wasn't aware that 2599 didn't use GTMxx. Garmin's product information on your unit and both the GTM60 & 70 indicate otherwise which is what i was relying on, look at these:
Seems Garmin doesn't know their own products [again] Have a great time in the states mate.Code:Please Login or Register to see the links