Or are we? What if evolutional pressure in different parts of the world has caused the translation to differ, based on different requirements for distinction and prioritization of colours?

Brown is either dark orange or dark yellow, but since differentiating ocher and umber browns has little significance to most people’s daily lives – as opposed to differentiating red and pink (flushed cheeks) pink and white (pale from sickness) etc, etc, we don’t bother. But when pushed we would of course acknowledge there are different browns, unless we have low grade color-blindness (can’t distinguish subtler color differences.)

My prediction is that there are other colors that fall outside of the spectrum but are not expressible with physical light. Our minds correlate color to a particular range of physical light because it is a simple way to distinguish between wavelengths, and noting contrasts is the basis for visual perception. If we argue from either a design perspective (God’s) or a adaption perspective (efficacy) we come to the same conclusion, and that is that we’re set up to translate a certain set of wavelengths to colors. This also means that it is possible we don’t really even see the same colors at all, though I think since we’re all similarly wired the translation should be similar enough.

I would stress that colors are ontologically real but also a continuum; therefore the breaking up of that continuum contains an additional meaning, whether descriptive of the actor’s history or perception, or of what the actor thinks colors should mean. Colors being continuous doesn’t argue for their being a construct or purely physical, it argues for their being infinite and thus always subject to remapping based on need.

(1) Color-qualia are real.

(2) Color-qualia tend to correlate with certain spectra.

(3) Via (2), you can abstract away from the qualia to get colors which are comparable across minds

(4) Given (3), where you draw the lexical distinctions is a social construct.

(5) Given (1) to (4), languages divide up the color spectrum differently.

(6) Given (5), there’s no one ‘right’ way to divide up the color spectrum into core lexical color-items.

What RiverC said below, you are sneaking in a form of nominalism and relativism. You say the issue is that different languages divide up the color spectrum differently, but what is at issue is ontology (what exists or not). (1) and (3) make references to minds. (4) to (6) make reference to language. The only possible premise in your argument that actually latches onto reality is (2), but even there you are hedging your words with qualifiers like “correlate”. Other problems:

(a) (1) to (3) seem to imply that color needs minds capable of subjective experience. How do you explain life forms that don’t have shared minds or abstracta making use of color? E.g. plants and their many shades of green that help with sunlight. You might say this is from evolution, but this is just my point. There seems to be something mind-independent going on here, even if color consists of vague language predicates.

(b) The jump from (5) to (6) is a jump from what is the case, to what is not normatively the case. You need some extra premise why it is not normatively the case.

(c) (1) to (6) seem to rule out any sort of color science at all. The only things that exist in the scientific endeavour of color are minds and language. You might say this isn’t the case given (2), but you are universally quantifying over all languages in (5), this includes scientific papers and research, which have to be grounded in a language. (5) and (6) seem to undermine (2).

This may be so, but all languages will adopt all the color names when they need to do photorealistic painting, for the purpose of identifying the different shades in that art.

There are languages with larger color name inventories than English.

Of course, this is all about basic color names — there can be non-basic color names (blue-green, dark red, etc. — I think gold and silver aren’t considered basic color names, though I’m not sure why), and between derivation and coining by analogy (see: ‘orange’), you end up with as much specificity as you’d need.

There’s something interesting going on here: on some level it’s all relative [and therefore seemingly random], but on another level, it’s shaped by certain societal forces, technological demands for specificity, etc.

So on the most primitive level, there’s a totally linear gradient from less to more developed, with the West (and especially England) being most developed of all; but on closer examination, this breaks down and it’s all random and relative once you get past colonialist ideology and Western supremacism and so on; but on even closer examination, societal and technological demands imply the existence of some sort of advancement-gradation, since advances in certain fields (which demand specificity of color-names) will end up creating a wider vocabulary of color-names…

…and then, on a fourth level, that can be attacked, since there are languages in Papua New Guinea where certain areas of the color spectrum aren’t lexicalized at all and colors are described by analogy, which presumably would allow at least as much specificity as the English derivation system, but investigation of color names is restricted to basic (i.e. neither derived [dark red is derived from red] nor reducible to a more basic color [maroon is a type of red, but red isn’t a type of anything else] — cf. vörös [ = dark red], which is neither derived from nor reducible to piros [ = red]) color names and that ignores the potential for derivation and analogy and there really ought to be terms for the things that are going on here but there aren’t…

The whole ‘a country where the trees are blue’ probably glosses the fact that ‘tree blue’ and ‘lake blue’ would have been understood as distinct shades of ‘blue’ anyway. The whole color relativist position is a way of using a mess of information to confuse and obscure, the very opposite of science.