Add user language chooser to wp-signup.php

[johnbillion]

After core implemented a site language chooser during install (#28577), the language chooser was also added to the Sites -> Add New screen (#33528) and to wp-signup.php (#33844).

Core now has a per-user admin language setting (#29783). There's a ticket for adding the language chooser to the Users -> Add New screen (#38665).

This ticket is for investigating whether a language chooser should be added to wp-signup.php when a new user account is registered. The workflow is a little more complicated because it's possible to sign up for just a user account or a user account and a site at the same time and it needs to be clear which language chooser corresponds to the site language, and which to the user language (if indeed they're to be two separate settings).

[desrosj]

@ocean90 @swissspidy do you have any opinions here?

[johnbillion]

Not much traction on this and my gut feeling is that wp-signup doesn't get a whole lot of use, so closing this for now. If someone wants to pick it up, go for it.