I discovered that light magic was the source of my newfound auditory capabilities. I only knew this because during those rare times that the diary was not soaking in white magic, acoustic quality noticeably suffered.
It was not too difficult to hear voices through my pages as the girl kept rather loud company. Of course, I couldn't understand what was being shouted. Judging by the frequency of the use of certain words, I wager that my holder's name is 'Kagome'. This Kagome would often say with affection or worry 'Sango', 'Miroku', 'Shippo', and 'Inuyasha'. That last one was often said rather loudly and was sometimes accompanied by anger. Occasionally, I would hear her shout an 'Osuwa….something' which was followed by a warming of light magic and a sound of a thump. I would also gamble that this Kagome was my main source of good magic.