[Experience Cloud] Site language is not reflected for self-registered users

The Experience Cloud site's standard self-registration feature does not allow setting a language other than the organization's 'Default Language' upon user creation.

To change the user's language setting, the user must log in to the site after their account has been created and follow these steps:

1. Log in to the Experience Cloud site.
2. At the top right of the screen, click the [User Icon] > [My Settings].
3. Change the [Language] to the desired setting and save.

It may be possible to set the language selected with the language selector by setting the [Registration Page Type] to [Configurable Self-Reg Page] and developing a self-reg handler (Apex).