On Earth, a free-falling object accelerates at 32 feet per second. This means that after two seconds the object is falling at 64 feet per second, and after three seconds it's travelling at 96 feet per second, and so on.
The object's velocity continues to increase at the same rate until it reaches its terminal velocity, which is when air resistance equals the force of gravity. When the terminal velocity is reached, a free-falling object can no longer accelerate. In a vacuum, a feather falls at the same rate as a hammer because there isn't any air resistance to slow either object down.