O ftentimes people do not realize they're dead right away. They don't usually figure it out until they realize time is no longer linear. Additionally, they are able to be in many places at one time. Each thought they have results in an immediate change. Whatever they think materializes.
Events seem disjointed yet make sense at a symbolic level.
Verbal language is no longer needed, yet some spirits still use it on occasion. It is a perfect body in that it takes the form that suits our immediate purpose. It's dynamic in that it is ever-changing as our thoughts about ourselves change. We can change form very easily and often do without even realizing it. When we wish to materialize in the physical world, we often adopt the body which was known to others.