Tested with: debian-live-buster-DI-a1-i386-gnome.iso in a Qemu virtual machine. Boot menu option (example): Debian Live with Localisation Support -> Spanish (es)
Environment variables seem right and make effect over interface words, but "Input Sources" in desktop environment not: "English (US)" anyway. Can be seen with: gnome-control-center region -- __________ I'm using this express-made address because personal addresses aren't masked enough at this mail public archive. Public archive administrator should fix this against automated addresses collectors.