Wikipedia is a free multilingual open-source wiki-based online encyclopedia edited and maintained by a community of volunteer editors, started on 15 January 2001 as an English-language encyclopedia. Non-English editions were soon created: the German and Catalan editions were created on circa 16 March,[1] the French edition was created on 23 March,[2] and the Swedish edition was created on 23 May.[3] As of April 2024, Wikipedia articles have been created in 342 editions, with 329 currently active and 13 closed.[4]
The Meta-Wiki language committee manages policies on creating new Wikimedia projects. To be eligible, a language must have a valid ISO 639 code, be "sufficiently unique", and have a "sufficient number of fluent users".[5]
Wikipedia projects vary in how they divide dialects and variants. For example, the English Wikipedia includes most modern varieties of English including American English and British English.[6][7] Similarly, the Spanish Wikipedia includes both Peninsular Castilian and Latin American Spanish,[8] and the Portuguese Wikipedia includes both European Portuguese and Brazilian Portuguese.[9] In contrast, some languages have multiple Wikipedias. For example, Serbo-Croatian encompasses four Wikipedia editions, Serbo-Croatian and three different standardized varieties (Bosnian, Croatian, and Serbian).[10]
Additionally, some Wikipedia projects apply different approaches to orthography. For instance, the Chinese Wikipedia automatically transliterates between six standard forms: three using simplified Chinese characters (Mainland China, Malaysia, and Singapore) and three using traditional Chinese characters (Taiwan, Hong Kong, and Macau).[11][12] And rather than relying on transliteration, Belarusian has separate Wikipedia projects for the official Narkamaŭka and Taraškievica orthographies.[13]
Each Wikipedia project has a code, which is used as a subdomain of wikipedia.org. The codes mostly conform to ISO 639-1 two-letter codes or ISO 639-3 three-letter codes, with preference given to a two-letter code if available.[14] For example, en stands for English in ISO 639-1, so the English Wikipedia is at en.wikipedia.org.
The table below lists the active language editions of Wikipedia roughly sorted by magnitude of the number of active users (registered users who have made at least one edit in the last thirty days).[15]