How do I get the /right/ answer out of it, not just any old rubbish?

You work out for yourself how to make the 9 character addition to the snippet I posted required to get the answer you need.

use strict;
use warnings;

use Win32::API::Prototype;

ApiLink( 
    'kernel32.dll', 
    'LONG GetSystemDefaultLangID( VOID )'
) or die "Can't import GetSystemDefaultLangID: $^E\n";

my $langid = GetSystemDefaultLangID( 0 ) & 0xffff;

if (defined $langid) {
  print "Returned '$langid'\n";
  printf "Lang ID: 0x%04X\n", $langid;
}
else {
  print "Returned <undef>\n";
}
__END__
P:\test>369060
Returned '1033'
Lang ID: 0x0409
[download]

Of course, I could have searched through the header files, looked up what a LANGID was, and added these characters to my post, but I didn't have any real interest in doing that. You need the solution, not me.

Perhaps I could clean your keyboard for you?