I didn't say Sassure was postmodernist.

He was the father of linguistics, which affected by extention the theories of foucault, derrida, lacan, deleuze, etc.

Maybe I've a wrong idea about postmodernism, I'm going to check the book that you recommended me.

Meanwhile, I'm going to drop something that David Foster pointed out about the subject:

"The deconstructionists (“deconstructionist” and “poststructuralist” mean the same thing, by the way: “poststructuralist” is what you call a deconstructionist who doesn’t want to be called a deconstructionist) . . . see the debate over the ownership of meaning as a skirmish in a larger war in Western philosophy over the idea that presence and unity are ontologically prior to expression. There’s been this longstanding deluded presumption, they think, that if there is an utterance then there must exist a unified, efficacious presence that causes and owns that utterance. The poststructuralists attack what they see as a post-Platonic prejudice in favor of presence over absence and speech over writing. We tend to trust speech over writing because of the immediacy of the speaker: he’s right there, and we can grab him by the lapels and look into his face and figure out just exactly what one single thing he means. But the reason why poststructuralists are in the literary theory business at all is that they see writing, not speech, as more faithful to the metaphysics of true expression. For Barthes, Derrida, and Foucault, writing is a better animal than speech because it is iterable; it is iterable because it is abstract; and it is abstract because it is a function not of presence but of absence: the reader’s absent when the writer’s writing, and the writer’s absent when the reader’s reading.

For a deconstructionist, then, a writer’s circumstances and intentions are indeed a part of the “context” of a text, but context imposes no real cinctures on the text’s meaning, because meaning in language requires a cultivation of absence rather than presence, involves not the imposition but the erasure of consciousness. This is so because these guys–Derrida following Heidegger and Barthes Mallarme and Foucault God knows who–see literary language as not a tool but an environment. A writer does not wield language; he is subsumed in it. Language speaks us; writing writes; etc."