The Basque language is really odd. Really really odd. It's a bit like finding an elf in a zoo. All the other animals, even the stick insects and the tigers, are related to each other, however distantly, but the elf...wow.
How did an elf happen?
No one knows how the Basque language happened, either. There are various guesses, but no sooner does someone come up with some supporting evidence then it gets shot down in flames.
The most popular theory is that the Basque language developed in the Basque region in France and Spain from...well, from no language that's left any trace anywhere else. This would probably mean that the Basques haven't mixed with other people much, but DNA shows...well, it shows all sorts of things, including a surprising kinship with the Welsh and Irish.
Other theories link the Basque language with the ancient Iberian language, the Caucasian languages, and the Berber and Phoenician languages, but none of the evidence for any of these theories is anything like good enough.
So where does that leave us?
Well, I suppose all we can do is listen to the Basques themselves. The claim is that the Basque language is the most difficult in the world, and they explain this with the story that it was taught to the Basque people by the devil himself.
...but why would the devil bother to teach the Basques his own language? He's already a hundred per cent fluent in every language there is.
Word To Use Today: Basque. This word comes from the French, and before that from the Latin Vasco. Before that things get mysterious. The word might come from a possible Celtic word barscunes, meaning the mountain people, the tall ones or the proud ones. Or it might use the proto-Indo European root, bar- meaning border, frontier, or march.