function singularize($word)
{
$singular = array('/(quiz)zes$/i' => '\\1', '/(matr)ices$/i' => '\\1ix', '/(vert|ind)ices$/i' => '\\1ex', '/^(ox)en/i' => '\\1', '/(alias|status)es$/i' => '\\1', '/([octop|vir])i$/i' => '\\1us', '/(cris|ax|test)es$/i' => '\\1is', '/(shoe)s$/i' => '\\1', '/(o)es$/i' => '\\1', '/(bus)es$/i' => '\\1', '/([m|l])ice$/i' => '\\1ouse', '/(x|ch|ss|sh)es$/i' => '\\1', '/(m)ovies$/i' => '\\1ovie', '/(s)eries$/i' => '\\1eries', '/([^aeiouy]|qu)ies$/i' => '\\1y', '/([lr])ves$/i' => '\\1f', '/(tive)s$/i' => '\\1', '/(hive)s$/i' => '\\1', '/([^f])ves$/i' => '\\1fe', '/(^analy)ses$/i' => '\\1sis', '/((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)ses$/i' => '\\1\\2sis', '/([ti])a$/i' => '\\1um', '/(n)ews$/i' => '\\1ews', '/s$/i' => '');
$uncountable = array('equipment', 'information', 'rice', 'money', 'species', 'series', 'fish', 'sheep');
$irregular = array('person' => 'people', 'man' => 'men', 'child' => 'children', 'sex' => 'sexes', 'move' => 'moves');
$lowercased_word = strtolower($word);
foreach ($uncountable as $_uncountable) {
if (substr($lowercased_word, -1 * strlen($_uncountable)) == $_uncountable) {
return $word;
}
}
foreach ($irregular as $_plural => $_singular) {
if (preg_match('/(' . $_singular . ')$/i', $word, $arr)) {
return preg_replace('/(' . $_singular . ')$/i', substr($arr[0], 0, 1) . substr($_plural, 1), $word);
}
}
foreach ($singular as $rule => $replacement) {
if (preg_match($rule, $word)) {
return preg_replace($rule, $replacement, $word);
}
}
return $word;
}