Changing the default language makes the selected language the new source of truth. Its stored translations are removed because that content is now expected to be authored directly. The primary storefront also switches to the new default.
If the selected language is not enabled yet, it is added when your plan has room. Otherwise, remove another non-default language first.
- Choose Set as default beside the new source language.
- Review every warning shown.
- Confirm the change using the confirmation action.