I experimented and found the following:
Say range is 50m in a sphere.
Shout range is 500m in a sphere.
Distance is calculated by Pythagorean distance sqrt(North^2 + East^2 + Altitude^2). Note that it does not match Track distance! I’ve seen track distance to be wrong (480m tracked would not hear the Shout)
You can turn on shout by typing /shout with nothing next to it and pressing enter. Or you can click the small box in the chat to select /shout.