Jalvic peoples can into glorious empire. For this reason, they only have three colour terms, except those in contact with Kangshuic mountain yak herders who know the secret of what a yellow is.

...is the basic story. I figure the three colours in question are red/black/white but I don't actually know a lot about three-colour languages and/or the realism of such a language being used at court in megavietnamese maritime trading empire, so I have so far refrained from being any more detailed.