Since it takes "their language" so literally as to have English majority nations with a different word listed, I wonder how many other countries on this don't actually use their version of thursday.
This map is not about a nation's word for Thursday but about the word in different languages. Austria for example isn't labelled with any word because Austrians speak German and the German word for Thursday is already placed in Germany. The English word Thursday is placed in England, its most logical location. The Gaelic word for Thursday meanwhile is placed in Scotland, its most logical place. This doesn't imply that the majority of Scottish people speak Gaelic, only that Scotland is the country with the highest number of Gaelic speakers while England has the highest number of English speakers in Europe.
Yes I understood that, but I'm saying it would be interesting to know which other places is a similar situation of not a regularly spoken language. Since I don't speak any Scandinavian language and know very few latin languages, I have no context of which of these are historic etymologic notations versus a word people actually use, but I bet there are a lot of them.
Political maps are a terrible tool for visualizing cultural / linguistic practices (and on this one, colonization didn't make it even worse). Just gotta roll with it and enjoy the weird assumptions :)