Back in the day, Google use to launch specific algorithms in different regions. Like with Panda, when it launched, it launched in English regions only at first. Then it was pushed to other language afterwards. With Panda, Panda was more about the content on the page, so language support took longer. But with Penguin it was more about links and content language was not so important, so it was a global launch.
Gary Illyes from Google said now, when Google launches new algorithms, they try hard to make sure it is a global launch. He said on Twitter, "nowadays we're working hard launching everywhere at once."
Here is the tweet:
It has been a while since Google confirmed any ranking algorithm changes, although we have covered many many unconfirmed Google updates. So this is probably all theoretical now anyway.
Forum discussion at Twitter.