Writing that is read will necessarily be personalized by the reader. It seems arguable that writers could also personalize what they write as coming from from them, when it might be coming through them. A radio does not create the music it amplifies. The radio is not the origin of the music it amplifies. The radio converts sound waves in the air into vibrations our ears perceive as music thanks to our ear drums.
Both writer and reader engage writing and written language through the process of meaning-making in the same way an individual exploits patterns s/he perceives to make sense of the external world. While we can speak of the transmission of info via written language as a technical and biological process (occuring systematically in brains), this is not the same as saying the reader or writer will have any awareness of their own mechanations of thought.
I am told electricity traces routes in my brain, firing bells and whistles that lead me to feel and think. When I have a thought or a thought occurs to me, I am not conscious of the biological nor the physical mechanics enabling or spawning that thought. My consciousness of the text I create enters once I’ve personalized it – made it relevant to myself? Just like a computer is not aware of it own processes and algorithms, so we could be too with our words?