Although Everett has been studying the Pirahã (pronounce pee-da-ha) Amazonian tribe, and their unique language since the 1970’s, his work remained relatively obscure until 2005, when an article he’d published on his website was then published in Cultural Anthropology.  According to Everett’s studies, the Pirahã’s language lacks many aspects of language that linguists argue are basic necessities of a universal grammar, such as color concepts, perfect tense, quantity concepts, and numbers over two.  Why?  According to Everett, their hunter-gatherer lifestyles have such little use for these concepts, that words to convey them simply don’t exist.  This research, which overtly repudiates the Chomskyian theory that has dominated the study of language for decades, has been called by Steven Pinker, “A bomb thrown into the party.”

The coverage of this study has greatly expanded recently, exemplified by this New Yorker articleLanguage Log has some excellent links concerning the Piraha.