I don't now. I read it. It seems that given that most of the documentation of the language was done by Everett, the Chomskians have some difficulty getting around some points.

I found the discussions of anumeracy in that PDF quite problematic because they basically argued we don't know enough about the language to say one way or another. Some of the difficulties, particularly adding vs removing spoons posed significant interpretation problems for me. Of course if I was differentiate between a few spoons and a bunch of spoons, the lines would be different if adding spoons vs subtracting them. This is because the relative frame of reference is different.

It seems to me that the problem is fraught with insurmountable epistemological problems which can't be solved and therefore people get to make best guesses. In general though I would trust the one who speaks the language more fluently than the one who doesn't. This isn't to address novelty claims. Bahasa Indonesia, for example, mostly lacks relative tenses as well, and Proto-Indo-European probably did as well.

It's clear that Everett has a lot more work to do before any of his claims will stand up to scrutiny.

Like I said earlier, it all sounds a little too perfect. Unpolluted by outside contact (because they refuse to learn a language that can't be whistled), the Piraha have no need for past, future, creation myths, kinship systems beyond the first degree, numbers, and so on. It's a dream of what we might be like if we were freed of our corrupt culture.

Is Everett an heir to Margaret Meade?