I've heard his linguistics work is genuinely remarkable, and as someone with a passing interest in the topic I'd be curious to check it out.
His linguistics work is an awful scam which set the field back decades. Advances in the study of
poorly-recorded indigenous languages (particularly those in South America) and
psychology have both shown his understanding of universal grammar to be horrifically wrong. By contrast, the work
others were doing in linguistics at the same time -- particularly Joseph Greenberg's use of mass comparison -- has been
hugely vindicated by modern archaeogenetics; more attention given to them would've given us a better understanding of prehistory at an earlier date.
Also, genocide apologist and anti-capitalist. HP.
Poll
