TextCat

I appear to have TextCat on my server:

locate TextCat
/usr/lib/perl5/vendor_perl/5.8.5/Mail/SpamAssassin/Plugin/TextCat.pm
/usr/lib/perl5/site_perl/5.8.5/Mail/SpamAssassin/Plugin/TextCat.pm
/usr/share/man/man3/Mail::SpamAssassin::Plugin::TextCat.3pm.gz
/usr/share/man/man3/Mail::SpamAssassin::Plugin::TextCat.3pm

I think I have it enabled in local.conf:

loadplugin Mail::SpamAssassin::Plugin::TextCat

Why does it not add any headers to messages indicating language? Any
idea what I am doing wrong?

Matt