Excellent! Since the worms are well out of the can (and pretty fast too!), can I add s|z, (f|ph) and add a plural case (rather than just making a singular)?

  ...
# $string =~ /^(.+)es$/ && push @patterns, $1;     # singular
  # Bliako modified:
  ($string =~ /^(.+?)(e?s)$/ && push @patterns, $1)     # singular
  || push @patterns, $string.'(e?s)?'
  ;
  s/(?<![sz])(?:s|z)(?=[^\)\.])/(?:s|z)/ for(@patterns);
  s/f|ph/(:?f|ph)/ for(@patterns);
  #print "patterns:"; print " /$_/" for(@patterns); print "\n";
  # end mods
  ...
[download]