Let me share some issues about 4.0 language…

Let me share some issues about 4.0 language switching functionality.

  • Current implementation for 4.0, adding new languages is not automatic. To get a new language to show up in the language switcher in the admin area, users have to manually copy language files to wp-content/languages directory. For example, if an initial installation is made as English (United States) and later the user wants to switch to other localesLocale Locale = language version, often a combination of a language code and a region code, for instance es_MX denotes Spanish as it’s used in Mexico. A list of all locales supported by WordPress in https://make.wordpress.org/polyglots/teams/ (his/her native localeLocale Locale = language version, often a combination of a language code and a region code, for instance es_MX denotes Spanish as it’s used in Mexico. A list of all locales supported by WordPress in https://make.wordpress.org/polyglots/teams/, etc), the user have to obtain the language files from somewhere, upload them to the right directory, and finally change it through the language switcher.
  • WPLANG constant is semi-deprecated and doesn’t work like before. It is used as a fallback when English (United States) or empty language option is selected. For example, if an initial installation is English but your wp-config.php has WPLANG with non English locale, WPLANG’s language files are automatically installed during the installation process.

See: https://core.trac.wordpress.org/ticket/15677

Releasing local packages as usual might be a good idea since it contains local language files in the first place. That always guarantees users to have a choice to switch back to his/her local language without complicated manual steps.