>In that, people literally cannot see the difference between blue and green if their language does not have words to distinguish them.

People literally can see the difference between blue and green even if their language doesn't differentiate between the two, I don't know if you're misremembering a claim and a negation sneaked in so please don't take this post too harshly if that's the case, but the idea that say Japanese people can't tell the difference between blue and green is patently false and should be addressed, in fact the video you linked almost does so at 2:34 -

>Some researchers took this and other ancient writings to wrongly speculate that earlier societies were colour blind.

That Homer described the ocean as wine in colour is not an issue of perception but one of language in trying to describe a colour that is not differentiated from other colours, the same is true for other 'perception' issues in the ancient world like green coloured honey. To be clear visual acuity tests have been done on modern populations and tribes which don't differentiate between such colours or overall define less colour categories and it should be no surprise to learn that they can see the difference between those colours just fine.

The whole idea that it's a difference in perception is fraught with issues, like what happens when a language naturally develops words for new categories of colours or new colours? Does a generation undergo the collective experience of literally being able to see/differentiate a new colour? If so why isn't this written about more, is it something that only happens in kids? What would be the reason for this sudden shift in perspective, because it certainly isn't a physiological change that occurs.

What happens when an adult learns a second language which differentiates between more colours? The classic romanticised view here is that learning a new language literally let's you see the world in a different perspective, but then why is it that enhanced perspective rarely more than a curiosity (language x has two words for this colour)? The Russian language has separate words for a dark blue (siniy) and a light blue (goluboy) but English doesn't differentiate between them, do the Russians see an extra colour? What does the science say? Well the science is somewhat interesting here, Russians are able to differentiate between dark blues and lighter blues ever so slightly faster (124ms), but this is worlds apart from the claim that some languages are literally capable of seeing more colours.

In general this line of thinking is known as linguistic relativity, or the view that language shapes perception and cognition, and is something that has generally been discredited among linguists as being discriminatory and harmful as well as being based on faulty reasoning or studies and occasionally fraudulent papers. For example, and I really don't mean to attribute any malice to your post, but if we're considering Homer as being unable to differentiate between an ocean blue and a dark red wine, what do we make of cultures and languages that don't differentiate between smoking, drinking, or eating? Do they not know the difference between those actions? What about the Pirahã people who only have two words (differentiated by tone) for 'small quantity' and 'large quantity' and no other words for numerals? This line of thinking is fairly harmless when applied to the way we perceive colours but can be actively harmful to people who perceive the world the exact same way we do but don't have as expressive language for these particular topics.

For anybody interested in more linguistic oddities and/or the damage linguistic relativism can do I recommend the book 'The Language Hoax' by John McWhorter, there's also an hour long talk on it available on Youtube [0]. The book deals with the more recent studies on how language affects the ways we think in a grounded way and shows how minor some of the best examples given can be like in the case of dark and light blue in Russian. The book is also in response to the general public's view and romanticism of linguistic relativity and in particular in response to a book by another linguist Guy Deutscher titled 'Through the Language Glass', where Guy feeds into the perception that language helps shape the way we think, and it is a good book but it still doesn't get close to saying that other languages see more colours.

[0] https://www.youtube.com/watch?v=yXBQrz_b-Ng