PHP как сделать человекопонятный URL ЧПУ или семантический URL. Функция транслит русских букв.

function get_semantic_url($str1) {
    $tr = array(
        "А"=>"a","Б"=>"b","В"=>"v","Г"=>"g",
        "Д"=>"d","Е"=>"e","Ж"=>"j","З"=>"z","И"=>"i",
        "Й"=>"y","К"=>"k","Л"=>"l","М"=>"m","Н"=>"n",
        "О"=>"o","П"=>"p","Р"=>"r","С"=>"s","Т"=>"t",
        "У"=>"u","Ф"=>"f","Х"=>"h","Ц"=>"ts","Ч"=>"ch",
        "Ш"=>"sh","Щ"=>"sch","Ъ"=>"","Ы"=>"yi","Ь"=>"",
        "Э"=>"e","Ю"=>"yu","Я"=>"ya","а"=>"a","б"=>"b",
        "в"=>"v","г"=>"g","д"=>"d","е"=>"e","ж"=>"j",
        "з"=>"z","и"=>"i","й"=>"y","к"=>"k","л"=>"l",
        "м"=>"m","н"=>"n","о"=>"o","п"=>"p","р"=>"r",
        "с"=>"s","т"=>"t","у"=>"u","ф"=>"f","х"=>"h",
        "ц"=>"ts","ч"=>"ch","ш"=>"sh","щ"=>"sch","ъ"=>"y",
        "ы"=>"yi","ь"=>"","э"=>"e","ю"=>"yu","я"=>"ya"," - "=>"-"," – "=>"-","--"=>"-","---"=>"-","----"=>"-",
   "."=>""," "=>"-","?"=>"","/"=>"-","\\"=>"-","!"=>"",
   "*"=>"-",":"=>"-","*"=>"-","\""=>"-","<"=>"-",
   ">"=>"-","|"=>"-","»"=>"-","«"=>"-","#"=>"","$"=>"","("=>"",")"=>""
    );
    return strtr($str1,$tr);
}

$string = 'как сделать семантический URL';
echo get_semantic_url($string);