How does one use Cyrillic (or other) characters in a statement where mb_strpos doesn't apply?

Basically, if($host == 'site.com/music/') works but if($host == 'site.com/музыка/') does not (there is no PHP error, but it moves on to the "else" section).

Substituting unicode escape sequences doesn't work; PHP simply ignores the Cyrillic part (as if to simply say if($host == 'site.com//'). mb_strpos isn't an option as I need an exact match in this instance.