From page xiv of For they know not what they do:
The crucial point here is that Freud's famous ambivalence of libidinal states has nothing whatsoever to do with some biological or psychological-affective oscillation, but refers strictly to the radical gap between literal meaning and underlying intention. The minimal structure of this reflexivity is, of course, that of poetic repetition: if I say "window", it is just a simple designation; however the moment I say "window... window", a gap separates the word from itself, and it is in this gap that the poetic "depth" resonates. And the truth of the old cliche about the "poetic origins of speech" is that there is no single occurrence of a word: repetition always-already resonates in it. It is crucial to perceive the link between this self-reflexivity and failure: the reflexive turn towards self-awareness occurs when there is a "malfunction", when things no longer run smoothly.A first reaction: Why isn't "Window" by itself already poetic? (Indeed, Zizek seems to say it is. Then what is the contrast between the "window" and the doubled "window"?)
I actually was not aware that "the poetic origins of speech" was commonly-repeated enough to count as a cliche, but I will take Zizek's word for it that it is. It occurs to me that the truth of the cliche is more likely to lie in the fact that "poetic" communication is possible without language; birds have sing-song, after all, and apes can hoot and howl in harmony. These are seen as a kind of music, and thus as at least a cousin of poetry; humans are then thought to have simply added something else to this hoot-and-howl base to get language. This strikes me as a reasonable chain of thought. Though of course it could be entirely wrong; biology is not an armchair discipline.
In a strong sense, "there is no single occurrence of a word" is clearly false. Novel vocabulary must begin somewhere, and wherever is first it will be singular (perhaps for a quite short time, but not for no time at all, at least not in all cases). In another sense it's clearly true -- a word can be repeated. A word which was only possible of being used once couldn't be used as a word at all. What this has to do with reflexivity or poetry, I haven't the foggiest. When a word is repeated, it's not talking about itself (as if it had to hunt down its previous instance and say "This is the word I am!"); it's doing what it did previously (to the extent that it does something else, it's not a repetition, but a new word -- perhaps a homonym).
Given that last bit I quoted, Zizek appears to be committed to the idea that (at least in principle) there might be language without self-consciousness (there is a "smooth" functioning of language before which there is no self-awareness). This strikes me as a very bad thing to commit oneself to.
This reminds of a joke Aleister Crowley was fond of telling: We are aware of our stomach only when it is upset and grumbling; we are aware of our lungs only when we are panting or wheezing; we are aware of our heartbeat only when it is going rapidly or running irregularly; in general, we are aware of our organs when they fail in their proper function. But we are always conscious of our own minds. What does this tell us about our mental health?
(Picking apart Crowley's joke will be left as an exercise to the reader. If you find yourself wanting to join the OTO, the you are taking the joke the way Crowley intended -- which means you are entirely in the wrong and should seek counsel immediately.)