To search/filter items by the active language and include items tagged with * (all languages) you will need Search operator plugin

  1. Create new text field with storage Standard-Article-Language. Set it's default value to * (field is named Article language all on the screenshot).
  2. Add the following fields to your search type, if you need just filtering this fields will be set to hidden variation:
  3. Set Article language field to use live value Variable --> language