"We can hardly conclude even so desultory a survey of grammatical misdemeanours as this has been without mentioning the most notorious of all. The anacoluthon is a failure to follow on, an unconscious departure from the grammatical scheme with which a sentence was started, the getting switched off, imperceptibly to the writer, very noticeably to his readers, from one syntax track to another. There is little to be said on the matter."

The anacoluthon is a rhetorical figure that occurs when a part of a sentence doesn't grammatically, or sometimes even logically, follow from the preceding part or parts.

This can be done intentionally:

I will have such revenges on you both,
That all the world shall - I will do such things,
What they are, yet I know not'
-William Shakespeare, King Lear, via xrefer.com

The indeterminacy of the sign- is this theory given its best evidence by the practice of E2 noders?

Or unintentionally:

She didn't say that, why did she say that?

As we have seen in our discussion of the modus morons fallacy, chronology does not imply causation, and it thus follows that aaaaaaaaaaaaaaaaaaaaaaaagh I'VE JUST BEEN SHOT!!!!

It is related to the anapodoton and the aposiopesis.

An`a*co*lu"thon (#), n. [Gr. , , not following, wanting sequence; priv. + following.] Gram.

A want of grammatical sequence or coherence in a sentence; an instance of a change of construction in a sentence so that the latter part does not syntactically correspond with the first part.

© Webster 1913.