My favourite part was this:
...some languages, like Matses in Peru, oblige their speakers, like the finickiest of lawyers, to specify exactly how they came to know about the facts they are reporting. You cannot simply say, as in English, “An animal passed here.” You have to specify, using a different verbal form, whether this was directly experienced (you saw the animal passing), inferred (you saw footprints), conjectured (animals generally pass there that time of day), hearsay or such. If a statement is reported with the incorrect “evidentiality,” it is considered a lie. So if, for instance, you ask a Matses man how many wives he has, unless he can actually see his wives at that very moment, he would have to answer in the past tense and would say something like “There were two last time I checked.” After all, given that the wives are not present, he cannot be absolutely certain that one of them hasn’t died or run off with another man since he last saw them, even if this was only five minutes ago. So he cannot report it as a certain fact in the present tense.
Imagine what the world would be like if this were true of all of us. Instead of saying "god is like this" one could only ever say "I believe god is like this", and instead of saying "you're going to hell", they'd only be able to say "I believe you're going to hell".
"That is sinful" becomes "My culture views that as sinful".
I think it would be a positive change.