Generally philosophical traditions seem to be associated with literate cultures. But a philosopher is someone who has a philosophical problem and so not necessarily tied to literacy.
Obviously literacy allows discussion over time & space, expands ways of thinking and allows a documentary record.
Is there any indication, that for say the pre-socratics, philosophy is primarily an oral activity, carried out in dialogue, rather than one carried out in writing.
I'm more interested in cultures outside the ambit of todays literate cultures.