Controlling the speed of servo?
In a normal position servo, 1mS will make it move from wherever it was to one end of its travel, at the fastest the servo can manage. 2mS will make it move to the other end.

If you step between 1 and 2mS length pulses, then it will do this as fast as it can. If instead you provide a ramp of intermediate length pulses, say 1.0, 1.1, 1.2 ... 1.9, 2.0mS, then it will move to each intermediate position along the way, effectively moving more slowly.

There are servos that behave as you say, 1mS makes it rotate one way and 2mS the other, but they are few and far between, and are often used for boat windlass duty, where rotation for many turns is required.