In Indian English, for large numbers, especially in financial contexts, lakh (100,000), Crore (10 million) are generally used, often multiplicatively (e.g 1 lakh crore for 1 billion). Very_ rarely, Arab ( 1 billion) is also used.
Numbers over 1 million were ambiguous at the time Indian English came into being -- 1 billion was either 1e9 (short scale), or 1e12 (long Scale), and is still ambiguous to older English-speaking Indians.
I once remember a letter in the Times of India sometime in the 1990's, by someone decrying a multi-billion dollar expense for a power plant (the https://en.wikipedia.org/wiki/Dabhol_Power_Station that was to be built by Enron, as the then largest ever foreign investment in India) was unaffordable and cost India years of GDP. Which makes sense if you're thinking in Long Scale terms.
"billion" meaning 10^12 was the norm in the English speaking world outside of the US up until the 80s/90s - I think that, at least for money, the American billion gets used, while the English billion wasn't very useful and so never got used - which is why the English billion dropped from use
What you refer to English billion (a million millions, rather than a thousand million s) is used in Europe instead of American billion. An European billion is an American trillion.
Yes - my point though is that usage of the American billion has taken over in the English speaking world largely because there is seldom a need for something the size of the English (or European ) one (except maybe for the American defence budget)
Can confirm, for French at least — “milliard” is exclusively used for 10^9, even for money. 10^12 is “billion” technically, but “mille milliards” is IME way more common.
A classic mistake made by new hires on the now-defunct Junglee.com (an Amazon property targeted to India but staffed largely by non-Indian developers) was to file an issue claiming that numbers like “1,23,000” were incorrectly formatted on the site, when in fact, that’s perfectly correct in the Indian English locale (one lakh, 23 thousand).
