Dynamics are written instructions that tell a performer how loud to play. They range from pianissimo or pp which is very soft, all the way to fortissimo or ff which is very loud.
This table shows how dynamics can be compared to the volume of the human voice.
|pp||almost at a whisper|
|p||softer than speaking voice|
|mp||soft speaking voice|
|mf||loud speaking voice|
|f||louder than speaking voice|