Hello Jhana4 all,
In the Buddha's day, writing was just for things like government and commerce. and there was widespread illiteracy. For really important things, where it was critical that no alteration occur ( as can happen so very easily, deliberately or accidentally when writing is used) - the Oral Tradition was used. The Buddha instituted in his lifetime the Chanting Together by large groups of specially designated Bhikkhus - the Bhanakas (Hearers). The Bhanakas had portions of the Teachings allocated to each group, and so there were The Digha Bhanakas, The Majjhima Bhanakas etc.
It was only hundreds of years later in Sri Lanka, in a time of famine and warfare, with many bhikkhus dying, and with Buddhism all but wiped out in India, that the MahaSangha decided the Buddhist Canon and its commentaries needed to be written down.
They were engraved on Ola Leaves. Many of us have been to Sri Lanka and have had the inestimable good fortune to have seen demonstrations of this being done at the ancient rock temple of Aluvihara Temple (where the Tipitaka was originally written down) in the Matale district 26 km from Kandy.
The Suttas are rather like the memory prompts - the dot points of the most important information to be transmitted - similar to those a public speaker carries on a little card in his hand. Anything that is repeated is to be seen as something important which was highlighted by the repetition.
As I understand it, the Pali Suttas are teaching vehicles whose meanings are densely packed layer on layer. They are not to be read as an ordinary page of print, but require 'unpacking' by someone learned in the Dhamma. This condensed form was necessary in order that the Teachings would not be lost in the years before they were finally put into writing. It allowed them to be memorised by the large groups of bhikkhus (bhanakas) assigned to each portion of the Tipitaka. They are not verbatim reports of chats and conversations. This memorisation is said to have commenced before the parinibbana of the Buddha.
"Thus you should train yourselves: 'We will listen when discourses that are words of the Tathagata -- deep, deep in their meaning, transcendent, connected with emptiness -- are being recited. We will lend ear, will set our hearts on knowing them, will regard these teachings as worth grasping & mastering.' That's how you should train yourselves." (Ari sutta).
Venerable Mahá Kassapa, the elected head of the First Council. Cúlavagga Xl,1,1 (ii,284) reiterated:
"Come, friends: let us recite the Teaching and the Discipline before what is not the Teaching shines forth and the Teaching is put aside, before what is not the Discipline shines forth and the Discipline is put aside, before those who speak what is not the Teaching become strong and those who speak what is the Teaching become weak, before those who speak what is not the Discipline become strong and those who speak what is the Discipline become weak."
---The trouble is that you think you have time---
---Worry is the Interest, paid in advance, on a debt you may never owe---
---It's not what happens to you in life that is important ~ it's what you do with it ---