Regardless of whether you believe the Quran is the word of God or not, pronunciation and the use of diacritics were issues early on in the history of Islam. In around 650 AD, the caliph Uthman noticed small differences in pronounciation, as the Rashidun expanded to Mesopotamia, Syria, North Africa, and Iran. He set up a committee to examine these differences, eliminated those versions exhibiting the differences in pronounciations, and recomplied all of Muhammad's(SAW) revalations, which had previously been preserved orally or on fragments of written parchment, until they were put to a single book very soon after the death of Muhammad(SAW), by Abu Bakr(RA) after many huffaz died in the Ridda Wars. What if the compilation of the Quran had been worse, that new versions had appeared, and new suras not part of the original canon, that the diacritic and pronunciation reforms were not carried out, and that the different versions, proliferated not only in other dialects beside the Quraishi one, but even versions adopted for non-Arabs, diverge from the original Quran in being physically altered. It is not a question of interpretation of words, which themselves are the same, but physically divergent Quran's, claiming to be the original revelations of Muhammad by his followers. What would be the effect on Islamic law and jurisprudence, and what new sects could such a thing spawn? Would Arabic itself split up into different languages, like what happened with Latin in Europe(granted, the circumstances were wildly different, but the Quran really was a touchstone of the Arabic language)? What would be the effect on culture?