This policy should not be taken as a precedent for a proposal to close existing wikis that do not meet these criteria.
A language must be sufficiently different, in its written form (taking into account the possibility of automatic conversion between different forms when lossless conversion is possible), from a language that already has a wiki (see the complete list of Wikimedia projects). This issue is to be decided by the following test: If contributions in Language A are not accepted in any Wikipedia as-is (ie, the language will be changed), then it may be considered separate. Where this is controversial, consensus may be necessary as well.
The proposed language must exist in a standard written form, preferrably one supported by the latest version of the Unicode standard.
For any natural language, at least 2 speakers with a (near) native level of fluency, and an additional 3 users of any existing Wikimedia project must support the request publicly.
There is no minimum number of native or fluent speakers or readers for natural languages.
If there is a consensus on requests for new languages after two weeks of the initial listing, a message should be sent to wikitech-l, asking a developer to set up the wiki.
In cases where there is not consensus after two weeks, it is up to the requester to find this consensus, be it through discussion, polling, etc.
Artificial languages will need to gain consensus within the Wikimedia community before they can be created. It is up to the requester to find this consensus, be it through discussion, polling, etc. Let the proposer be warned that most artificial languages, and especially fictional languages, are unlikely to be created.