Preferences → User profile → Internationalisation: Language
The language selection in Preferences has a large number of selections, but defaults to en. Changing the language does not translate pages; for example, setting en-gb for British English does not change color to colour in articles.
The language selection allows localization for messages. Many system messages that appear in the Wikipedia interface are stored in the MediaWiki namespace. Each of those pages has a version for each language selection. Many of those interface pages do not exist by default or have been heavily customized for the English Wikipedia. Only a very few of the non-en pages have been customized. You can view system messages through Special:AllMessages and select the desired language.
Examples:
- The message that appears at Preferences → Signature
en:Treat the above as wiki markup. If unchecked, the contents of the box above will be treated as your nickname and link automatically to your user page.
If checked, signing with ~~~ or ~~~~ will insert the above markup in place of your username, including any wikicode or formatting. Custom signatures should link to your user page, your user talk page, or your contributions.
Do not use images, transcluded templates, or external links in your signature. Please ensure your custom signature complies with the relevant guidelines.
Note: to use a displayed pipe ("|") character (i.e. not part of a piped link), please use | for the pipe character; otherwise, it may cause templates to fail.en-gb:Treat signature as wikitext (without an automatic link to your user page)