how to month name translate Turkish ?
You should have a language file in /locales/vf_tr_TR/definitions.php which begins like that:
$LocaleInfo['vf_tr_TR'] = array (
'Locale' => 'tr_TR',
Where is your language file and what does it look like?
Explanation: Vanilla uses the function strftime: http://php.net/manual/tr/function.strftime.php
This function shows dates based on the "locale" which is set based on the "Locale" that you find in the language file.