Dan Everett believes that Pirahã undermines Noam Chomsky’s idea of a universal grammar.
Well I can tell you from personal experience that if I was a betting man I'd bet against recursion because I don't believe it's built into anyone's brain.
I know it didn't come natural to me and took many years to even understand what it really means.
I mean turtles all the way down?
What's that supposed to mean?