The evolution of the terms for "blue" and "green" is one of the most fascinating topics in linguistics and cognitive science. It reveals a surprisingly universal pattern: across human history and geography, blue is almost always the last basic color to be named.
Here is an explanation of why this happens and how the "blue-green" distinction evolves.
In 1969, researchers Brent Berlin and Paul Kay published a groundbreaking study showing that languages don't just pick color names at random. Instead, they evolve color terms in a predictable, specific order.
Most languages follow this trajectory:
- Stage I: Black and White (or Dark and Light).
- Stage II: Red.
- Stage III/IV: Green and Yellow (in either order).
- Stage V: Blue.
- Stage VI: Brown.
- Stage VII: Purple, Pink, Orange, Grey.
Key Insight: A language will rarely have a word for "blue" if it doesn't already have a word for "red" or "green."
Before a language develops a distinct word for blue, it typically lumps blue and green together into a single category that linguists call "Grue."
To speakers of "Grue" languages, the sea, the sky, and the grass are all roughly the same shade. It’s not that they physically cannot see the difference (their eyes work the same way ours do); it’s that their culture has not yet needed to make a linguistic distinction between the two.
Examples of Grue:
- Japanese: Historically, the word Ao covered both blue and green. This is why Japanese traffic lights (which are green) are still referred to as "Ao" (blue) signals, and why distinct words for green (Midori) are a relatively modern invention.
- Welsh: The word Glas historically covered blue, some greens, and even shades of grey. Today, Glas is blue and Gwyrdd is green, but the history remains in phrases like "glaswellt" (blue-grass) for green grass.
- Vietnamese: The word Xanh can refer to both the blue of the sky and the green of the leaves. To specify, speakers add context: "Xanh of the sky" or "Xanh of the leaves."
Why do humans consistently name red, yellow, and green before blue? There are two main theories:
A. Rarity in Nature Blue is incredibly rare in nature.
- Red is the color of blood and danger; it is evolutionarily critical to spot.
- Green/Yellow are the colors of vegetation, ripeness, and food sources.
- Blue appears mostly in the sky and the distant sea, neither of which you can interact with. Blue animals and plants are very rare (even "blue" birds are often just performing light tricks with their feathers, not using blue pigment). Because early humans couldn't pick up, eat, or dye things blue, they didn't need a word for it.
B. The "Lazarus" Theory (Technology) Linguist Lazarus Geiger analyzed ancient texts (including the Bible, the Koran, and the Iliad) and noticed a pattern: Civilizations develop a word for blue only when they learn to make blue dye.
- The ancient Egyptians were the only ancient culture to have a specific word for blue—and they were also the only culture producing blue dyes at that time.
- In the Odyssey, Homer famously describes the "wine-dark sea." He never calls it blue, because the Ancient Greeks did not yet have a word for that specific part of the spectrum. They likely viewed the sea as "dark" rather than a specific hue.
As civilizations advance technologically and begin manipulating pigments, the "Grue" category splits.
- Dark/Cool separation: The language splits Grue into "Dark/Cool" (Blue) and "Light/Vegetation" (Green).
- Russian/Greek Split: Some languages have evolved past English in this regard. Russian, for example, does not have a single word for "Blue." It has two distinct basic categories: Siniy (dark blue) and Goluboy (light blue). To a Russian speaker, these are as different as "Pink" and "Red" are to an English speaker.
The evolution of blue and green is a story of necessity. Humans name what they interact with. We interacted with blood (red) and plants (green) long before we could interact with the color blue. Consequently, for thousands of years, humanity looked at the sky and saw "darkness" or "grue" rather than the blue we see today.