Languages genuinely divide the colour spectrum into different numbers of basic categories — Russian distinguishes two blues English treats as one, while Japanese historically used one term for what English splits into blue and green — a difference in vocabulary and habitual categorisation, never a claim about what speakers can actually perceive.
Russian has two distinct basic colour terms, goluboy (light blue) and siniy (dark blue), where English uses one word, 'blue', for both.
Russian
Historically, Japanese used one term, ao, to cover what English now splits into 'blue' and 'green'; a traditionally 'green' traffic light is still called ao shingo in Japanese.
Japanese
When two languages divide colour differently, the measurable consequences are small and specific. Experiments compare how quickly or accurately speakers tell two shades apart, or how well they remember one, depending on whether their language puts a word boundary between them. Where an effect appears it is a matter of milliseconds or of recognition scores, and it does not always replicate. English itself is a good witness that vocabulary can change while vision does not: it had no single word for orange until the 1510s or for pink until the 18th century, and in Middle English 'yellow' could be used for a colour nearer blue-grey. Speakers saw those colours perfectly well; they filed them differently. 1, 2, 3
Each row applies only to the tradition, place and period named in it, on the authority named in it.
| Tradition | Where | When | According to | What is recorded | Sources |
|---|---|---|---|---|---|
| Greek speakers | Laboratory study led from Bangor University | study published 2009 | Thierry and colleagues, PNAS | Greek has two terms, ghalazio and ble, for light and dark blue. Brain recordings showed Greek speakers responding more strongly than English speakers to a change between blues, an automatic effect that appears before conscious attention. | 1 |
| Russian speakers | Laboratory studies | 2007 and 2020 | Winawer and colleagues, PNAS; Martinovic and colleagues, Cognition | A first study found Russian speakers quicker to discriminate shades falling either side of the boundary between goluboy and siniy. A later re-run of the tasks was published under a title announcing the limits of that influence. | 4, 2 |
| Himba-speaking children | Namibia | study published 2009 | Goldstein, Davidoff and Roberson, Journal of Experimental Child Psychology | Himba has no separate terms for green and blue. In a memory task the children showed no advantage for pairs that cross the English green–blue boundary, behaving like English children who had not yet learned their colour words. | 5 |
| Somali speakers | Comparison with English speakers | study published 2020 | Lindsey, Brown and Lange, Cognitive Science | Some speakers named both green and blue samples with one term, and that term was not simply the English 'green' and 'blue' added together. | 6 |
| Speakers of 110 unwritten languages | World Color Survey | data archive | University of California, Berkeley | An average of 24 speakers of each language named and chose best examples from a standard array of 330 colour chips, giving the largest body of comparable naming data. | 7 |
| English speakers of earlier centuries | England | Old and Middle English | Online Etymology Dictionary | Old English 'red' covered shades now called purple, crimson, scarlet and pink, and the French word behind 'blue' could also mean pale, wan or blond. | 3 |
Generalisation: People whose language has no word for a colour cannot see it.
Evidence: Not what any of these studies shows. They measure differences in discrimination speed, automatic brain responses and memory between groups who can all see the stimuli. Where effects are found they are modest, and a re-run of the Russian tasks reported limits to the effect. The history of English, which gained 'orange' and 'pink' late, is a plain counter-example. 1, 2, 5, 3
Every claim above is scoped by the specific culture, region and/or period it applies to — none of these associations are presented as universal. See pigment and dye history for more.