[tex-live] babel doesn't know USenglish anymore

[Sven Köhler]

Hi,

since an upgrade to TeXLive 2017, babel doesn't know the option
USenglish anymore. Using the option usenglish (lower case) works with
TexLive 2017, but does not work previous versions. The current
documentation of babel still calls the option USenglish (with upper case
US) and it seems that this writing is supposed to be the right one.

The problem is caused by the fact that the file installed by TexLive
2017 is called usenglish.ldf, not USenglish.ldf. This matters, on UNIX
at least. Ironically, usenglish.ldf contains the line
	\ProvidesLanguage{USenglish}

It seems, that earlier babel versions had a document option USenglish
which simply loads english.ldf. With recent versions however, there is a
usenglish.ldf and babel.sty doesn't provide a document option USenglish
anymore. Long story short, it seems USenglish is now implemented
differently and is currently broken.

I'm using TexLive 2017 as installed by Gentoo Linux.


Kind Regards,
  Sven