5 ideas
In a culture without writing, a thought that is not cast in memorable form is effectively lost, because there is no external place to look it up. Oral thinking therefore has to be built from rhythm, balanced patterns, repetition, antithesis, alliteration and proverbs, and the need to be memorable shapes what can be thought at all.
Oral performers compose from stock phrases and epithets such as 'wise Nestor' or 'the sturdy oak'. These are not clichés but retrieval units that let a speaker rebuild long narratives in real time. The formula is the unit of memory, which is why oral cultures prize the familiar phrase over the original one.
Because knowledge dies unless it is constantly repeated aloud, oral societies spend great energy restating what they already know and elevate elders who hold it. Redundancy and copiousness in speech keep speaker and listener on track when there is no text to glance back at. Innovation happens through adapting old material to present audiences rather than through overt novelty.
Without writing to hold knowledge apart from people, knowledge stays embedded in live struggle between persons. Oral cultures therefore favour verbal contest, such as flyting, riddling, boasting and ritual insult, along with fulsome praise. Learning is tied to confrontation between people rather than to detached analysis.
Writing, and later print, are not neutral recording tools but technologies that separate the knower from the known. That separation enables abstraction, lists, precise definitions, introspection and analytic distance. Many habits we treat as natural rationality are artifacts of literacy, and oral thought is situational and participatory rather than inferior.