Your concept as Quran is written.
Our concept of Quran is literal. The written Quran validates what is passed down orally through generations as in the past most people are illiterate and recite it from memory, till today.
Your oral concept of the quran came from the literal quran.
Before the quran was compiled, no single person memorized the entire 'revelation' of muhammad, which was 'revealed' over a period of twenty years and recorded on separate parchments/scrolls. Each memorizer would only have bits and pieces of muhammad's revelation. To memorize the entire quran, the hafiz, or memorizer, would have to refer to the written quran after all the different manuscripts were put together. And that's before having to argue which arabic dialect is the real version of the quran, since there were supposedly around 7 dialects of the quran circulating even during the time of muhammad.