no need to add any additional code to fit your language special chars
just on Outputfilter.seo.php
Code:
$name=strtr($name,"ŠŒŽšœžŸ¥µÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏĞÑÒÓÔÕÖØÙÚÛÜİßàáâãäåæçèéêëìíîïğñòóôõöøùúûüıÿİIı",
"SOZsozYYuAAAAAAACEEEEIIIIDNOOOOOOUUUUYsaaaaaaaceeeeiiiionoooooouuuuyyiii");
just change this line to suit your needs.
For example i add İIi to change to iii at the end of the line bolded