This article is from the Recreational Figure Skating FAQ, by Karen Bryden with numerous contributions by others.
The mohawk and choctaw involve a step from one foot to the other
during the execution of the turn.
Mohawk. A Mohawk is a change of direction (eg. forward to backward)
while skating on an arc of a circle. It includes a change of skating
foot and retains the same character of edge (eg. forward inside to
backwards inside). The edges before and after the turn are on the same
lobe. Because of the use of both feet, there are only 4 Mohawk turns,
depending on whether the entry edges is inside or outside and forward
or backwards. There are however, many variations on the execution of
the Mohawk turn within this analytical constraint.
Choctaw. A Choctaw is a change of direction (eg. forward to backward)
that involves both a change of skating foot and a change in the
character of the edge (eg. backward outside to forward inside). The
edges before and after the turn are on different lobes having opposite
directional curvature. Like the Mohawk, there are only 4 Choctaw