Add functions to pluralize and singularize English nouns

Thanks, Owen. Before I commit it, we do require an update for the documentation as well.

I saw that. Thank you.

Committed to both branches.

The following:

  foreach ($irregular as $plural => $singular) {
    if (preg_match('/('.$plural.')$/i',  $word, $arr)) {
      return preg_replace('/('.$plural.')$/i', substr($arr[0], 0, 1).substr($singular, 1), $word);
    }
  }

overwrites the $plural variable used earlier in the pluralize_en function.

Also, the foreach should be foreach ($irregular as $singular => $plural), based on the format of $irregular.

Same goes for the singularize_en function. Here is a patch to fix that.

pluralize_en is currently returning false in development version when it should not.

Might this have to do with multi-byte characters?

Not sure about the other stuff, but the overwriting issue noticed by jpmckinney is still a problem in the current development version. In this case using singularize_en, we've got:

  $singular = array (
    '/(quiz)zes$/i' => '\\1',
    '/(matr)ices$/i' => '\\1ix',
    ...

  foreach ($irregular as $plural => $singular) {
    ...

  foreach ($singular as $rule => $replacement) {
    ...

By the time we get to "foreach ($singular as $rule => $replacement)" the value of $singular has already been overwritten by "foreach ($irregular as $plural => $singular)".

jpmckinney's patch fixes this issue.