访问不同类的静态参数中的类的静态参数

I'm trying to access a static paramter of a class, witch instance is stored in a static paramter of another class. This is how it looks like.

parent::$model = new $model(); 
parent::$model::$lang = $lang_id;

php is respoding with "unexpected '::'" on the line where I'm trying to store $lang_id. Please tell, if this is even posiible in php and eventually how do I do it. Thank you in advance.