This feels like a “falsehood developers think about localization.”

It’s always funny when I get French YouTube ads. As if YouTube is desperately trying to offload the adbuys anywhere they can by pretending that Canada must mean French.

I think the whole point is for it to be a static site that is easily distributed with little-to-no overhead, as it probably receives a non-trivial amount of traffic.

That assumes that (i) every region has a primary language, and (ii) everyone in that region speaks that language, both of which are false.

(And false often enough that guessing language based on IP address works badly in practice, I hear.)

Just check the Accept-Language header

I believe it's just using the official languages of the UN