Languages as in knowing two systems. Sort of like how most people don’t need to know international date or thousands/decimal separator conventions, but those functioning internationally—whether due to being well travelled or senior enough to conduct international trade and/or relations—do.
My going to a conference in India and arguing over the lakh/crore system isn’t useful to anyone [1].
Even then, continents have little to do with it. The Indian numbering system is indeed used in much of Asia - but it's not used in Russia for example. If you live in Vladivostok, you might need to learn these two systems even if you never do business with anyone farther than 300km from you.
And in Europe there are numerous differences between countries of this kind - Germans and a few others use different number separators (1,000 is 1000 in France or the UK or Spain, but 1 in Germany or Romania). Several places drive on opposite sides of the road. The UK uses many imperial units. I'm sure there are others I haven't even come across yet.
> (1,000 is 1000 in France or the UK or Spain, but 1 in Germany or Romania)
No, France and Spain follow the same standard as Germany: dots as thousands separators, a comma as the decimal separator. Actually most of Europe does the same, the only exceptions being the UK and Ireland:
My going to a conference in India and arguing over the lakh/crore system isn’t useful to anyone [1].
[1] https://en.m.wikipedia.org/wiki/Indian_numbering_system