Five hundred millionth user

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(English) This is an essay. It expresses the opinions and ideas of some Wikimedians but may not have wide support. This is not policy on Meta, but it may be a policy or guideline on other Wikimedia projects. Feel free to update this page as needed, or use the discussion page to propose major changes.
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The five hundred millionth user is the worst user of English on Earth. The basis for this assumption is that about 500,000,000 people speak English, or say that what they speak is English. The person who does so least well is the five hundred millionth user! This person is able to read the wiktionary (maybe) and simplified wikipedia (maybe, if the defining vocabulary is all right), but there's little or no hope that s/he can read the wikipedia in present form.

One view is that the needs of this user should be considered before the needs of the one billionth user or three billionth user, who do not speak English at all. This would focus us more on vocabulary and less on translation.

Who says they're reading the English-language section?

Since this is the English meta, it seemed appropriate to think about the five hundred millionth user of the English version;
There is no "English meta". Meta-Wikipedia is officially multilingual, though it is presently mostly in English.
However even if that person is reading a non-English version, there will be at least some of the articles that are translated from very common languages like English, Chinese or Spanish. Some estimates show that Chinese will pass English in 2006 as the most used language on the Internet. These 'takeup rates' must be taken into account in terms of how much energy goes into solving problems (like capitalization and character support and old browser/hardware support) that might be specific to a community of language users. So, you're invited to outline some best cases where English vocabulary and especially defining vocabulary are either solved problems, or irrelevant because almost all articles have good original authors willing to write in almost all common languages.
Even if there are, though, the hundred millionth user and five hundred millionth user will probably still be reading articles that were translated (well or badly) from English. By the one billionth user it seems more feasible that original authors would be working in all of the most common languages, and by the three billionth user that the less common languages would be covered as well.
Can you suggest a different way to express the wikipedia user base and its projected growth? If the five hundred millionth user is 50% likely to speak English and 28% likely to speak Chinese and 15% likely to speak Spanish, we should say that and anticipate the problems of cross-translation here.