Link for the Science research article. The observation that societies without access to softer food kind of avoided labiodentals is old, from 1985, but the research is recent-ish (2019).
My favourite bit of this is the comment at the bottom of the page that just says “doubt it”. So glad scientific discourse is alive and well.
I’m glad, too. This sort of scepticism is one of the pillars of science. Like, just because it seems solid (it does, for me) it doesn’t mean that it’s true.
A factor not mentioned by either the research nor the article is that [f v] sound considerably sharper than [ɸ β], so there are contrastive reasons to shift the fricatives from bilabial to labiodental if the effort necessary doesn’t make them too convoluted to pronounce.
