Multiple segment moves are designed to work with an even spacing between the linear positions. This will result in a uniform speed along that axis. It's possible to shorten or lengthen the distance between segments, resulting in a change in the linear speed (and/or not changing the linear position within a segment to result in no linear movement.) However, this may not work in all situations. See video below for more information (forward to 1:00)
Axis - Referring to the movement of an individual motor. Pan, Tilt, Focus, Linear (slider).
Segment - Distance between two keyframes. Number of segments is one less than the number of keyframes set. For example: 4 keyframes will have 3 segments.