Consider the old example:
All men are mortal. Socrates is a Man. Therefore Socrates is mortal.
Consider someone who understood the first two propositions, but who could not see that *therefore* the third was true.
The failure of this person to make the leap from the first two propositions to the third is *not* a failure that takes place in language. That is, one of the most elementary moves of the intellectu is extra-linguistic or non-linguistic. It is an instance in which clearly knowledge exists independently of language.
It is a failure of intuition. Faced with a failure of intuition no explanation can be made verbally.