- Since the value for $this->post_type won't be known at translation time (only at runtime), the call to _x() is not translatable. The second parameter for _x() should be an actual string, so the call can be properly translated. If it's a variable, the context is effectively unknown at translation time. Replaced with plan __() for the time being. To properly translate post-type labels, if we want context, we should create a separate source file for label declaration for each post-type.