If Auto Dashboard Language is installed and activated, the browser language preference is used to determine the WordPress Dashboard and widget language.
1) User visits WordPress site
2a) If the user is NOT logged in (anonymous):
The language preference set of the browser is compared to the installed WordPress languages. If any browser language in is installed, it is set as language for the user. If not, the global site language is used.
2b) If user is logged in:
If the user has a profile language configured (not equals ‘Site Default’) this language is used. If not:
The language preference set of the browser is compared to the installed WordPress languages. If any browser language in is installed, it is set as language for the user. If not, the global site language is used.
Plugin also fixes other plugins that don\’t recognize the profile language setting yet (introduced in WP 4.7).
If you use a caching plugin for anonymous users and wan’t to prevent presenting some of your widgets in a random users preferred language (when page is saved in cache) add define(‘WSADL_SKIP_ANONYMOUS’, true) to wp-config.php .