Once you save the options for your site's default language or a custom language, changing the language code requires you to follow a multi-step process. This involves adding a new language language, duplicating the content to the new language, and erasing the old content and language. It is not possible to change the language code directly.
What are the exact steps I need to take to change the language code for a specific language?
If you want to use a different code for a specific language, for example, jp instead of ja for Japanese, or if you want to change the language code for a specific language you have to do following:
- Add or create the language you need.
- Bulk duplicate the content to the new language from the WPML → Translation Management page.
If needed you can also:
- Export and import .po files from the WPML → String Translation page.
- Completely delete the old content and the old language from your site.