Manual:$wgLoginLanguageSelector

Language, regional and character encoding settings: $wgLoginLanguageSelector
Show a bar of language selection links in the user login and user registration forms.
Introduced in version:	1.7.0 (r14901)
Removed in version:	Still in use
Allowed values:	(boolean)
Default value:	false
Other settings: Alphabetical | By function

Details

Set this to true to show a bar of language selection links in the user login and user registration forms. Edit the "loginlanguagelinks" message to customize these options.