How colors get their names AARON COHEN · JUL 04 2012
On this day full of red, white, and blue in the US, it's interesting to note that, in a large number of languages, when colors start getting their own words, red is usually the first color defined after black and white (or light and dark), and that blue and green are often not defined individually, at least at first. Those facts and more in this super long/interesting article about color and language and how colors got their names and and and...just read it already. Here's part 2.
The figure above is really telling a story. What it says is this. If a language has just two color terms, they will be a light and a dark shade - blacks and whites. Add a third color, and it's going to be red. Add another, and it will be either green or yellow - you need five colors to have both. And when you get to six colors, the green splits into two, and you now have a blue. What we're seeing here is a deeply trodden road that most languages seem to follow, towards greater visual discernment (92 of their 98 languages seemed to follow this basic route).