Imagine you are boiling an egg and it develops cracks. Very quickly the white of the egg will cook on the outside of the egg. It is no longer a uniform egg shape but a structure with potentially multiple points of stability. This image
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represents a good likeness of what we think the interior of what the earth looks like. If a structure rotates, it will continue to do so as long as there is a single point of stability or if no external action is applied to it to change the orientation.
The has been an observable change in the position of the magnetic poles which has been advancing rapidly in the last few decades.
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By itself this is of of interest but coupling the indication that the Earth's spin is speeding up, things might get really interesting. If you have ever experience the clutch of a car fail perhaps while driving up the hill, things seem to be going okay but then the car slows down despite the engine racing. There is a disconnection between the engine and the transmission. I am not sure if this is a good analogy but the increase in speed of Earth may be the an indication we are heading for a similar disconnection.
In various sources from around the world, there have been references to long days.
"Joshuas Long Day" is not an isolated one. There is indisputable evidence from the modern science of ethnology that such an event occurred as Joshua records. In the ancient Chinese writings there is a legend of a long day. The Incas of Peru and the Aztecs of Mexico have a like record. There is a Babylonian and Persian legend of a day that was miraculously extended. Herodotus, an ancient historian, recounts that while in Egypt, priest showed him their temple records, and that he read of a day which was twice the natural length of any day that had ever been recorded...
While I cannot believe this could be a frequent occurrence, perhaps all the sources are referencing a common event, much like the flood myths from the past. The reason that I question the frequency is consider what would happen to the large bodies of water that exist on the planet, if the planet stood still? Both the air and water would continue their motion due to inertia. What would happen if a sizeable body of water continues while the land remains fixed. Even the largest tsunamis would not compare. Having a wall of water 1000 ft in height is within the realm of possibility. I would not relish being on a coastal area when that happens.
A second possible outcome may also occur. Currently the angle of rotation is moving two very large blobs around the axis. A good explanation can be found in the video about the Dzhanibekov Effect.
While the conclusion that the Earth won't flip, it fails to consider that outside forces are working and may work on the planet. If the crust does disconnect from the core and massive movement of water covers the land masses, a flip might be inevitable.