In the cowboy books of my childhood, the natives regularly referred to the whites as having "white eyes and speaking with forked tongues."
The forked-tongue thing, as I understood it, was supposed to be a double reference to snakes and to double speaking, saying one thing and meaning another or saying two things at once, two different things at the same time. When someone "speak with forked tongue," in the fake-pidgin of these books, what is said can't be trusted, or at least can't be taken as plain and at face value.
Christopher Columbus' diary is like this.
It would be easy to take a lot of what he says as simply what he thinks or what he believes. As simply statements that stand for themselves. For example, Charles Lippy, in his intro to American religion, takes Columbus' statement that the indigenous peoples of the newly-discovered world "had no religion" at face value, and relies heavily on that statement to make a case for how horribly badly Europeans misunderstood the religious aspects of tribal life.
While, surely, the misunderstanding was (and, I'd argue, though Lippy doesn't, is) horrible, leaning too hard on Columbus' statement's probably not a good idea. Columbus does say they have no religion, but also he says, three days later, in the entry for 14 Oct., that the inhabitants "all came to the beach calling to us and giving thanks to God," and he also has, earlier, an account of how these people (or people he imagines to be these people) were not properly missionized and so "so many peoples were lost, falling into idolatry and accepting false and harmful religions."
So it's not really quite the case, as per Lippy, that Columbus just conceived of the "Indians" as a-religious, and thus easily convertable. He did, but also he didn't.
One way to make these different statements consistent would be to take Columbus as meaning they had no organized religion when he said they had no religion. One, that would be a more true statement, on his part, in that the groups’ Columbus encountered didn't have an organized religion in the typical sense of that, though obviously, and this is Lippy's point, they were quite religious and spiritual. Two, it would be possible to make the different things Columbus said not contradict each other. So, it'd be the more charitable reading.
The consistency shouldn't be overdone, though, as Columbus is classically inconsistent, and shifts, in his speaking, between multiple different and not-really reconcilable positions. All of his statements really have to be understood as embedded in certain contexts, as having certain ends in view, as always intent on constructing certain stories that appeal to different audiences.
He is making a religious appeal, in his diary, for example, pitching to the queen and her court a certain understanding of this adventure that is baptized in Catholicism -- framing it as most essentially an act of faith, befitting people of faith, for the sake of faith and the furthering of the faith, etc.
He is making, too, an appeal to the glory of the earthly kingdom he serves. He claims the lands for Spain, draws the initials of the king and queen in the sand of the island and puts little crowns over the tops of the initials, and he's talking about the riches to be found and captured and used for the glory of Spain, and putting the adventure he's on in the context of economic sense and promotion and profit for the country.
The latter is not entirely distinct from the former, nor is it the same thing, which makes this tricky.
It's generally been the case, for example, in middle school text books and basic American understanding, that the faith-frame is understood as being a sales job, totally in bad faith, in order to sanctify conquest. There's also a minority (a very small minority, whose history is generally not to be taken seriously), who have argued that the talk about gold and glory was the sales job, and done in bad faith, as an way to trick the king's money men and self-interested parties into financing a deeply religious and basically evangelical mission to lands unknown.
There's a third argument, too, that both arguments are really sales jobs, that Columbus himself doesn't ultimately truly care about God or gold at all, but is just in it for his own glory. He certainly does, in the diary, seem to have one narrative specifically constructed for posterity, one story specifically for the historians, so they can be sure to get down (as we'd say today) exactly how awesome "the admiral" was.
I'm generally suspicious of interpretations of bad faith, though. For one, they seem based on assumptions of what someone "really believed," which are normally more projections of what the interpreter finds believable.
Also, in establishing a deep suspicion towards one thing, they seem to always or at least almost always naively accept some other thing. It's almost like this attitude of suspicion guarantees one will be totally not-suspicious about something that should raise at least a little bit of the suspicion that's been disproportionately aimed like an army somewhere else.
There also seems to be this general sense or sentiment that people can't somehow speak as a way of making arguments, which they both do believe and which are really more arguments and attempted framings than statements of thought out positions. As if people aren't irrational, or aren't also always figuring out what they think as they're speaking, spinning stories and ideas and arguments and then, when they hear it, deciding how it sounds.
It seems quite possible, to me, that Columbus believed all three of these narratives -- adventure for the glory of God, and the glory of Spain, and for his own glory too – and held all of them rather loosely, and that statements should be understood not as final statements, but as embedded in on-going stories, in-process arguments, under-construction framings attempting to make sense (or the most sense) of what was going on.
Most of what happens in the diary -- particularly these meaning-making statements -- needs, I think, to be read as fork-tongued, as always being two things at once. If Columbus is going to be understood with any depth, instead of just misread in incredibly simple ways, it'll have to be in way that the good faith is understood as being in bad faith too, and the bad faith in good faith, etc., the arguments on-going, the stories inconsistent and under-construction. If it's all held loosely, as fork-tongued and double-spoke rather than simple and plain statements of thought-out belief, then there's a better chance of actually grasping what's going on with Columbus.
The inconsistencies have to be held, not eliminated, ignored, or smoothed out or made to go away. There have to be ways of reading that say, “it’s both,” and, “of course it’s this and also that,” and all the pieces don’t all go together in a rational, motive-causing consistent story. That's the tricky part of reading Columbus, which is also, of course, just a tricky part of reading.