For cyrillic letters those functions convert them into the corresponding ACSII-Code. So in databases you will see only plain latin letters and ACSII-Codes. But the result of converting vowel mutation looks strange.
The following exmaple shows how you convert every non latin letter or symbol into the corresponding ASCII-Code, so you can save it to the database and read it out by using html_entity_decode.
function convert_for_db($string){ $for_db = ""; for ($i = 0; $i < strlen($string); $i++){ if(is_latin_char($string[$i])){ $for_db .= $string[$i]; } else{ $for_db .= to_ascii($string[$i]); } } return $for_db; } function to_ascii($char){ $ascii = ord($char); return "".($ascii).";"; } function is_latin_char($char){ $latin_chars = array("a","b","c","d","e","f","g","h","i", "j","k","l","m","n","o","p", "q","r", "s","t","u","v","w","x","y","z"); return in_array(strtolower($char), $latin_chars); }