By no means do we have to reckon exclusively with oral
tradition... Personally I have... tried to typologize the so - called «prophetical literature» in two main groups: «The liturgical type» («liturgy» taken as a
purely form -
literary term) to be found in Nah., Hab., Joel, «Deuter - Isa,» et al., with real «writers» behind them, and probably from the very beginning taken down in writing, and «the diwan type» (no very good term, I admit), e.g., Am., Proto - Isa., etc., primarily resting on oral transmission...