Plural Literature Suffix

pluralexcep.php

<?php
// To extend $key => $value pairs further as exception gets identified
return array(
		'addendum'=>'addenda',
		'analysis'=>'analyses',
		'child'=>'children',
		'goose'=>'geese',
		'locus'=>'loci',
		'louse'=>'lice',
		'oasis'=>'oases',
		'ovum'=>'ova',
		'man'=>'men',
		'mouse'=>'mice',
		'tooth'=>'teeth',
		'woman'=>'women'
	);

pluralsuffix.php

<?php

function plural($word = '', $count=0, $return_count = 0)
// Example:
// echo plural('boy', 0); // 'boy'
// echo plural('mango', 2); // 'mangoes'
// echo plural('knife', 3, 1); // '3 knives'
// Limitation: can't convert to plural out of rules, like man : men / to handle this exception list is being used.
{
    /*
    General Plural Literature Suffix Rules: 
    [1.0] 'ies' rule    (ends in a consonant + y : baby/lady)
    [2.0] 'ves' rule    (ends in f or fe : leaf/knife) --- roof : rooves (correct but old english, roofs is ok).
    [3.1] 'es' rule 1   (ends in a consonant + o : volcano/mango)
    [3.2] 'es' rule 2   (ends in ch, sh, s, ss, x, z : match/dish/bus/glass/fox/buzz)
    [4.1] 's' rule 1    (ends in a vowel + y or o : boy/radio)
    [4.2] 's' rule 2    (ends in other than above : cat/ball)
    */

    # Use mb_substr for multibyte #

    // Normalize case, not even first letter plural as a number supposed to be placed before
    $word = strtolower(trim($word));

    // Define vowels, all non-vowel is consonant
    $vowel = array('a','e','i','o','u');

    // Prefix count with word, if specified
    if (preg_match('/^[A-Za-z]{2,}$/', $word)) // a noun should be 2 or more letter
    {
        if($count > 1)
        {
            $excep = include('pluralexcep.php'); // Load exception list
            if(array_key_exists($word, $excep))
            {
                $word = $excep[$word];
            }
            else if(!in_array(substr($word,-2,1), $vowel) && substr($word,-1)==='y') // Rule [1.0]
            {
                $word = rtrim($word,'y').'ies';
            } 
            else if(substr($word,-1)==='f' || substr($word,-2,2)==='fe') // Rule [2.0]
            {
                $word = (substr($word,-1)==='e') ? substr($word, 0, -2) : substr($word, 0, -1);
                $word = $word.'ves';
            }
            else if((!in_array(substr($word,-2,1), $vowel) && substr($word,-1)==='o') // Rule [3.1]
                || in_array(substr($word,-2,2), ['ch','sh','ss']) || in_array(substr($word,-1), ['s','x','z'])) // Rule [3.2]
            {
                $word = $word.'es';
            }
            else
            { // Rule [4.2], covering [4.1]
                $word = $word.'s';
            }
        } else if ($count < 0){
            return false; // No negate in real world object existance !!??
        }

        if(!empty($return_count)) $word = $count.' '.$word;

        return $word;
    }
    return false;
}