I would like to discourage the use of the word "billion". It means different things to different people. For reference, this title uses it to mean 10^9, but it can also mean 10^12. The official word for 10^9 is milliard, but hardly anyone knows what you mean when you say that, so I'd encourage the phrase "thousand million" - everyone will know what you mean when you say that and it's unambiguous. Or use scientific notation.
In the English speaking world "billion" only means 10^9.
See Wikipedia:
> This is now the most common sense of the word in all varieties of English; it has long been established in American English and has since become common in Britain and other English-speaking countries as well.
And as much as I hate it, when communicating in public what matters is the commonly used definition of the word, even if it's different that what that word meant a few years ago.
Nobody in a casual English (and Asian too from my experience) conversation will mean billion to be 10^12. English sphere predominantly uses the short scale.
That being said, there is no official word but two globally used scales.
Essentially the entirety of the anglophone world uses short scale numbering. I highly doubt anyone would interpret "billion" as anything other than 10^9 in English text.
