Only first letter
function mb_ucfirst($string, $encoding = 'UTF-8'){
  $strlen = mb_strlen($string, $encoding);
  $firstChar = mb_substr($string, 0, 1, $encoding);
  $then = mb_substr($string, 1, $strlen - 1, $encoding);
  return mb_strtoupper($firstChar, $encoding) . $then;
}