Archeological philologists and anthropological linguists are finding, through scholarship and increasing understanding of the ancient languages, that oral testaments did change. There are etymolotgical evolutions of language and cultural/societal shifts discerned in the oldets texts known to have been set down from oral traditions in pretty much all ancient oral to text writings – in other words, they find early period etymologies beyong overlayed with later etymologies in all manner of texts. There is no logical reason to presume Judaic oral testaments were any less prone to these alterations.