protected static function normalize($word)
	{
		$nword = '';

		$len = strlen($word);

		for ($i = 0; $i < $len; $i++)
		{
			$o = ord( $word[$i] );

			if ($o < 97)
			{
				// convert to lowercase
				$o += 32;
			}

			if ($o > 122 || $o < 97)
			{
				// skip anything not a lowercase letter
				continue;
			}

			$nword .= chr($o);
		}

		return $nword;
	}