It IS interesting, however, that an Arabic alphabet already existed and so Arabic could be written at the time of Mohammed. That means that the surahs could have been written down almost immediately instead of committed to memory. I guess it shows that Arab tribal culture was illiterate rather than aliterate at the time. The same was true of the old Norse epics--they possessed a form of writing but really didn't use it for centuries. Not sure what to make of that other than the fact that neither society had much use for administration at the time.