My b2evolution Version: 3.3.1

hey there.
i installed a new b2evolution blog system. i like it. i downloaded turkish language and install it.
So now. if i edit the conf/_locales.php turkish characters in menus, polls etc. shown normally but my post are full with ?????
if i use original _locales.php my posts are seems ok but in menus, polls, searchbar etc turkish characters has ???

so what i'm supposed to do?

(sorry for my bad english, ask me if you don't understand anything, and i need support fast please :) )