How can I make the language here in Turkish?
You should add this strings in your site_core.php.
$Definition['FlagForReview'] = 'Turkish text';
$Definition['FlagLinkContent'] = 'Turkish text';
When there is a need to add translations, you should better create a file /conf/locale.php
Since it should be a PHP file, the first line must be <?php and below should be the definitions