In stick welding, wire speed would be feed speed or how fast that rod burns.
Turn up the amps on a stick welder and the rod will burn faster and you will have to feed it faster.
Stick welding is constant current.
In stick welding the voltage changes when you lift the rod away from the puddle or closer to the puddle. The current stays the same.
Like in mig if the voltage is too high the rod or wire will be too far away from the puddle and lots of spatter and little penetration.
Either way if you want to use a faster wire speed or burn rod faster you need more current = more heat.
With thinner metals you need to use less heat to prevent burn through.
Smaller wire or rods, less amps, slower wire speed.