?????????????? ??? ???????????? ?????????, ?????????? mb_strings ??? ???????????????. 

function do_translit($st) {

$replacement = array(

"?"=>"i","?"=>"c","?"=>"u","?"=>"k","?"=>"e","?"=>"n",

"?"=>"g","?"=>"sh","?"=>"sh","?"=>"z","?"=>"x","?"=>"\\'",

"?"=>"f","?"=>"i","?"=>"v","?"=>"a","?"=>"p","?"=>"r",

"?"=>"o","?"=>"l","?"=>"d","?"=>"zh","?"=>"ie","?"=>"e",

"?"=>"ya","?"=>"ch","?"=>"c","?"=>"m","?"=>"i","?"=>"t",

"?"=>"\\'","?"=>"b","?"=>"yu",

"?"=>"I","?"=>"C","?"=>"U","?"=>"K","?"=>"E","?"=>"N",

"?"=>"G","?"=>"SH","?"=>"SH","?"=>"Z","?"=>"X","?"=>"\\'",

"?"=>"F","?"=>"I","?"=>"V","?"=>"A","?"=>"P","?"=>"R",

"?"=>"O","?"=>"L","?"=>"D","?"=>"ZH","?"=>"IE","?"=>"E",

"?"=>"YA","?"=>"CH","?"=>"C","?"=>"M","?"=>"I","?"=>"T",

"?"=>"\\'","?"=>"B","?"=>"YU",

);

foreach($replacement as $i=>$u) { 

$st = mb_ereg_replace($i,$u,$st);

}

return $st;

}