
I tested with first "de-latin1-nodeadkeys" / "de_DE.utf8" and then again default settings for "us". Also, selected german and english settings in GRUB.
Unfortunately, the system is then unbootable. LILO (?) writes "99 99 99 99 99 ..." on the console.

It is a vbox with prepared partition table, swap /dev/sda2 and root /dev/sda1, just as the original slackware installer has done prior for a default installation.
The installer seems to be useless for me. Sorry.

