Error in code to change language


Please , What is the error in this code below:
$idioma = substr($_SERVER[“HTTP_ACCEPT_LANGUAGE”], 0, 1);
switch($idioma){
case ‘ar’: //Caso seja português
sc_set_language(‘ar_sa’);
break;
case ‘en’: //Caso seja espanhol
sc_set_language(‘en_us’);
break;
default:
sc_set_language(‘ar_sa’);
break;
}

if(isset($_GET[‘lang’]) && !empty($_GET[‘lang’]))
{
switch($_GET[‘lang’]){
case ‘ar’: //Caso seja português =sc_set_language(‘sk;sk_sk’);
sc_set_language(‘ar_sa’);
break;
case ‘en’: //Caso seja espanhol
sc_set_language(‘en_us’);
break;
default:
sc_set_language(‘ar_sa’);
break;
}
}

But when I change ar_sa to ar it gets this error:

خطأ
iconv(): Detected an illegal character in input string

Thanks in advance for any one help me