Adobe 12040118 - After Effects Standard Tutorial page 208

Linear interpolation (top) causes sharp changes; Bezier interpolation (bottom) creates smoother changes.
Control speed between keyframes without using the speed graph
In the Composition or Layer panel, adjust the spatial distance between two keyframes on the motion path. Increase speed by moving one
keyframe position farther away from the other, or decrease speed by moving one keyframe position closer to the other.
More spatial distance between keyframes increases layer speed.
In layer bar mode or in the Graph Editor, adjust the time difference between two keyframes. Decrease speed by moving one keyframe farther
away from the other, or increase speed by moving one keyframe closer to the other.
Shorter temporal distance between keyframes increases layer speed.
Apply the Easy Ease keyframe assistant, which automatically adjusts the speed of change as motion advances toward and retreats from a