Localization files can be found in the /usr/local/vesta/web/inc/i18n/ directory. You can use en.php as a template to create new file. Just change the $LANG[‘en’] to $LANG[‘aa’] and you are all set.
In other languages some things are simply too long. You can rely on context to cut and shorten up long phrases. Instead of explicitly translate “Add Mail
Account” used “Add Account“.
Good luck!
