From Wikibooks, the open-content textbooks collection
This template displays the various language skill levels associated with a particular spoken language, the syntax for adding a userbox to one's user page to indicate one's skill level, and also provides links to jump to a particular skill level in the resulting listing of users proficient in that language.
Usage
{{User language category|language}} where "language" corresponds to the language code listed at Wikibooks:Babel.
Example
{{User language category|en}}
produces the following:
This category sorts English users by order of fluency (1 = native, 2 = nearly native, 3 = fluent, 4 = intermediate, 5 = basic).