Surely they mean "in the English system". In German, we have "Milliarde" between "Millionen" and "Billionen", and so on.
In fact, they will end on "-illion" if it's a power of 10^(6n) and on "-illiarde" if it's a power of 10^(6n+3).
Now, indeed, the split is roughly along the line of English (and Russian, Turkics and Arabic) on the short scale side and everyone else, especially Continental European language speakers on the other. It's not a universal rule: Brazil is maybe the largest defector from the Continental European group to the short scale, but Canada reinforces the rule by using both, with the choice being dictated by whether you're speaking English or French.
It's Wikipedia: feel free to click "Edit" and correct/update it.
For international purposes (america) this “long scale” fall out of use, with he “short scale” being recommended in the U.K. since 1974
I know a lot of people who didn't get that memo, because I still see the long scale with some regularity.
That said, the short scale is much more common overall.
Vestiges of it pop up from time to time. It's not really something you can Google directly for, but as an indication, literally the second hit on Google for "thousand million" - a term that only exists due to the long scale, and which is obsolete in the short scale - is an article about a Brexit-related bus ad:
https://www.independent.ie/world-news/and-finally/brexit-bus...
The best thing I can offer is that the word "billion" and greater should be regarded as cursed, ambiguous, and shouldn't be used any more.
Since Russia uses a short-scale system, the word is no longer in use. https://en.wikipedia.org/wiki/Long_and_short_scales