Tables:

tag:
  id:

tag_translation:
  id
  name
  lang


I have this content

2 tags in the tag table:

  tag:

   First record:

    id: 1

   First record:

    id: 2

3 records in tag_translation:

  tag_translation:

   First record:
    id:   1
    lang: es
    name: hola

   Second record:
    id:   1
    lang: en
    name: hello

   Third record:
    id:   2
    lang: en
    name: testing


How can i build a Doctrine_Query to get a list of spanish tags not translated to english and backwards?