Answer:
It can be incoherent. The sufferer may simply repeat everything you say to them. They may only speak a couple of words, and repeat them over and over again. They may speak aloud randomly whatever thoughts are in their mind. They may seem like they're talking to someone who isn't there.
Essentially disorganised speech refers to when a person does not appear to be speaking in an organised fashion which is understandable to anyone else other than themselves. It may seem like complete nonsense to use, but it may hold a heavy significance to them.