PHP plural to singular

I came across a small issue to display the singular version of any English word using some grammar rules to de-pluralise a word.

function depluralize($word){
    // Here is the list of rules. To add a scenario,
    // Add the plural ending as the key and the singular
    // ending as the value for that key. This could be
    // turned into a preg_replace and probably will be
    // eventually, but for now, this is what it is.
    //
    // Note: The first rule has a value of false since
    // we don't want to mess with words that end with
    // double 's'. We normally wouldn't have to create
    // rules for words we don't want to mess with, but
    // the last rule (s) would catch double (ss) words
    // if we didn't stop before it got to that rule. 
    $rules = array( 
        'ss' => false, 
        'os' => 'o', 
        'ies' => 'y', 
        'xes' => 'x', 
        'oes' => 'o', 
        'ies' => 'y', 
        'ves' => 'f', 
        's' => '');
    // Loop through all the rules and do the replacement. 
    foreach(array_keys($rules) as $key){
        // If the end of the word doesn't match the key,
        // it's not a candidate for replacement. Move on
        // to the next plural ending. 
        if(substr($word, (strlen($key) * -1)) != $key) 
            continue;
        // If the value of the key is false, stop looping
        // and return the original version of the word. 
        if($key === false) 
            return $word;
        // We've made it this far, so we can do the
        // replacement. 
        return substr($word, 0, strlen($word) - strlen($key)) . $rules[$key]; 
    }
    return $word;
}

I can’t claim that this was my work, but here is the authors link where I got this from.

//use it like so
echo depluralize('Products');// returns Product

https://sites.google.com/site/chrelad/notes-1/pluraltosingularwithphp

Happy days.

Valtid Caushi