Can the Earth's rotation reverse, like its magnetic polarity? Is there anything that could cause the earth's rotation to reverse?
The Earth's magnetic field can reverse if the electric currents generated in the core change direction.
The Earth's rotation however, has to obey the law of conservation of angular momentum. The only way the direction of rotation can be reversed would be to apply a huge force to slow the rotation down to a stop and then reverse it. The affect of such a force would be catastrophic.
The speed of rotation can be slowed by tidal locking. The Moon is tidally locked to the Earth which means that its period of rotation is the same as its orbital period. This is actually happening. The Earth's rotation is slowing down as angular momentum is being transferred from the Earth's rotation to the Moon's orbital rotation by gravitational effects.
It is however possible for the Earth's axis of rotation to flip through