I will speak, therefore, of a letter.

Of the first letter, if the alphbet, and most of the speculations which have ventured into it, are to be believed.

I will speak, therefore, of the letter a, this initial letter which is apparently has been necessary to insinuate, here and there, into the writing of the difference; and to do so in the course of a writing on writing, and also of a writing within writing whose different trajectories thereby find themselves, at certain very determined points, intersecting with a kind of gross spelling mistake, a lapse in the discipline and law which regulate writing and keep it seemly.  One can always, de factor or de jure, erase or reduce this lapse in spelling, and find it (according to situations to be analyzed each time, although amounting to the same), grave or unseemly, that is, to follow the most ingenuous hypothesis, amusing.  Thus, even if one seeks to pass over such an infraction in silence, the interest that one takes in it can be recognized and situated in advance as prescribed by the mute irony, the inaudible misplacement, of this literal permutation.  One can always act as if it made no difference.  And I must state here and now that today's discourse will be less a justification of, and evfen less an apology for, this silent lapse in spelling, than a kind of insistent intensification of its play.

           Jacques Derrida, "Difference," Margins of Philsophy, 3