Earlier quoted context omitted.
well that and the entire Mayan corpus. what pittance of codices we have today come from Christianized Maya scribes, a massively condensed post-columbian highlight reel of their obliterated textual culture compiled at the behest of the Spanish crown and under the direction of their Catholic overseers.
Also, languages like Guarani survived because of the efforts of missionaries (the Jesuits in this case). (But I will say that the current policy of "protecting" the isolated tribes in the Amazon from human contact by categorically shutting them off is quite horrible and uncharitable. This is rooted in the preposterous myth of the noble savage. Tribal peoples are not innocent children.)
I dunno. If you make contact with them, most of them will die of diseases to which they have no immunity. This happens over and over. Amazon tribes. Pacific islands. On a huge scale in the Americas. For those that do survive, the event may be so traumatic that they develop a very understandable hostility to outsiders.