how to notifyPropertyChange to rerender view in emberjs

Question

I need to rerender my main application view when app language change. I'm using ember-i18n that not support observing so i do some work to update view when language and lang property change. i switch lang in following action in my ApplicationRoute :

actions:
    {
       switchLang: function(lang){    

          this.get('controller.I18N').set('defaultLang', lang);

          //this.notifyPropertyChange('lang');

       },
    },

but i dont know how to notifyProperyChange to update or rerender my "applicationView" and template ??