> linguistic studies that show blue to be the last color named in virtually all languages

In Irish, the term "fear dubh" refers to the devil literally "black man" which presumably long preceded Irish language interaction with non-whites. To refer to a black (coloured) man in modern Irish the term "fear gorm" is used. The word 'gorm' in other contexts means blue. This would match your comment.

As an aside, the term "fear bán" is literally "white man" and I leave it to the curious to guess or research it's meaning.