Orality refers to the practice of oral tradition, history, and storytelling, just as literacy refers to those practices when they use the written word. Orality has made itself the dominant mode in the Fifth World, just as it had before the rise of civilization.
In an oral society, one learns in the context of a social relationship. Learning always takes place between people. Rather than discrete blocks, one learns through an ongoing series of conversations. This trains oral people to focus on continuous processes, rather than discrete units. The social context of learning colors everything you learn, showing you everything you learn through that filter.
This led to the re-emergence of orality after the collapse of civilization, as this focus on relationship helped create stronger community bonds and even helped them become better trackers, as they learned to focus more on relationships and continuous processes. Meanwhile, the day-to-day usefulness of information in books dwindled with each generation. After four centuries of this, orality became the dominant mode of transmitting thoughts, ideas, and information.
Literate people often think of oral tradition as horribly unreliable. They point to the game of “telephone” to illustrate how quickly and easily oral transmission can become corrupted. However, this game actually preys on some of the most particular weaknesses in human memory. We have a harder time remembering a random piece of information without context, we have a harder time remembering something without rehearsing it, and we have a harder time hearing the message in the first place when someone whispers it to us in a crowded room. Oral stories do the opposite of this, focusing on tricks to enhance human memory: using rhyme and music to make it more memorable, providing context, and creating the most effective space to learn and recite the stories.
Oral historians and storytellers pride themselves on their ability to recite long epics — some so long that they take several days to recite — “word for word.” That said, the word for “word” does not always translate quite as you might expect in a literal sense. Certain poetic formulations, like Homer's “wine-dark sea,” may count as a “word.” A “word” might even match more closely to the notion of a “beat” in a story.
The truth lies somewhere between the extremes of dismissing orality as completely unreliable and the claim that it can transmit data with perfect fidelity into perpetuity. In fact, data transmission does not matter nearly as much to oral people as to literate people. As mentioned earlier, the practice of orality trains oral people to focus on relationships, and oral tradition cares much more deeply about the relationships between people (human or otherwise) rather than faithful data transmission. Orality does not really allow for literalism, as the words themselves might suggest. Oral stories can change to reflect changing times, and to better help people relate to one another and to the world around them.
That said, oral histories have quite effectively preserved information even over tens of thousands of years — spans of time over which literate histories failed to preserve accurate or reliable information.