In general, as I understand it, there was only ever evidence for a weak version, and many of the cited anthropological examples that make the case turn out to have dubious factual basis - the old ‘Eskimos have hundreds of words for snow’ and ‘there’s a tribe in Africa who have no word for numbers greater than three’ stuff, all filtered through layers of academic anecdote and institutional racism.
Was there any substantial empirical reason it was "seen as a joke", or just changing philosophical fashion?