Where in the world are you getting these figures from? I would honestly like to know because that doesn't match up with information I've seen before. Truly if you have a source for that I would be interested, as all information I've seen in regards to this has been at least twice the amount of what you're saying.
"Approximately 330 to 360 million people speak English as their first language."
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, using "A History of the English language" (a 2006 publication from Cambridge University) as reference. We were 6.6 billions on Earth at this time and even if things have changed in 12 years, the rise in population actually happen outside of western's countries which tend to have a stable demographic curve. So the percent is still reliable ; It's perhaps 5.5% now, but well, lets say that I rounded it.
As for the 10% it's more a guess than anything else, since I didn't found information ; sorry, but babel isn't a reliable source, they are selling their products. But not a blind guess. The same Wikipedia page, using the same reference, state that : "Estimates that include second language speakers vary greatly, from 470 million to more than 1 billion. David Crystal calculates that, as of 2003, non-native speakers outnumbered native speakers by a ratio of 3 to 1."
Considering that only 1 out of 3 end being fluent in their second language seem right for me. Most of them learned it because it can be useful, but in the end don't really need to use it in their everyday life. There's few exceptions, like Nordic countries, where many peoples are fluent in more that two languages, but they tend to have a small population.
Note that this is true for English, and probably also French and Spanish, which are the most used languages all around the world, but obviously wrong for other languages because there's initially less people knowing them in your own country. You'll end using it, while for English (and French and Spanish), there's always someone who was in the company before you and are the one who will handle the English speaking ; especially since he know the people he will speak with, which isn't your case yet.
While I understand what you are saying, I am going to have to disagree with you on whether you're confusing people or not. Being a native English speaker doesn't matter anywhere near as much as I believe you're crediting it to be.
That was the meaning behind my, "in fact, sometimes you probably also confuse people who are native English speakers, but never had to listen people talking with "this" accent and so aren't really sure of what they read.".
I fully understand that being a native English speaker isn't enough and that a Canadian speaking to an Australian will have hard times to understand each other ; hell, sometimes I don't understand half what a guy living at 200km form me is saying, so two people from different countries... And inevitably, when these differences are translated in words, even native English speakers can be confused by the fact that the author suddenly use a Turkish word ("yer", thanks to google translate and
@Lykanz I now know a Turkish word).
[...] while it obviously isn't statistically or scientifically backed as I'm speaking from personal experience I would be willing to hazard a guess that within at least the English language, this is extremely common and a facet of life for anyone speaking English in the world.
Which was my main point. Using English as language for a game is a necessity since it's a language you can expect to be spoken all around the world. But starting to write with an accent, or using localized phrasing, will mostly let you with only the people living in your country ; and still probably not all of them. This whatever it's an English speaking country or not. I can't imagine what English speakers, whatever native or not, would think reading a game wrote with the French accent.
