In the mid-1960s Berlin and Kay ended up at Berkeley. They had their graduate students scour the Bay Area for native speakers of foreign languages, quizzing them with standard color chips, not unlike those used as samples for paint. Their object was to establish the meanings of basic color terms--that is, those that could not be analyzed into simpler terms (such as 'blue-green') and were not defined as characteristic of a given object (such as 'salmon'). Later Berlin and Kay collaborated with other researchers to expand their sample to 110 languages.
Color lexicons vary, first of all, in sheer size: English has 11 basic terms, Russian and Hungarian have 12, yet the New Guinean language Dani has just two. One of the two encompasses black, green, blue and other 'cool' colors; the other encompasses white, red, yellow and other 'warm' colors. Those languages with only three terms almost always have 'black-cool,' 'white-light' and 'red-yellow-warm.' Those having a fourth usually carve out 'grue' from the 'black-cool' term.
The tree of possibilities turned out to have branching points, some of them rather rare. Still, the manner in which languages can build up their color words is tightly constrained, suggesting the existence of universal constraints on semantic variation.
I've always been a sucker for Spair-Whorf, relatively speaking.