A model Mixin to use in translatable applications, to use inherit your models from this

mixins.py

class TranslatableModelMixin(models.Model):
    '''
    Adapted from http://snippets.dzone.com/posts/show/2979
    '''
    language = models.CharField(max_length=2, choices=settings.LANGUAGES, db_index=True)
    translation_of = models.ForeignKey(
        to='self',
        related_name='translation_set',
        limit_choices_to={'language' : settings.DEFAULT_LANGUAGE},
        blank=True,
        null=True,
    )


    def get_root_translation(self):
       """Returns the root translation for this page.

       This page will be in the settings.DEFAULT_LANGUAGE."""
       if self.translation_of is None:
           return self
       else:
           return self.translation_of

    def get_translations(self):
        """Return all of the translations for this page."""
        # If I am the root translation, just return all of my translations.
        if self.translation_of is None:
            return self.translation_set.all()
        else:
            # If I am not the root, return the root translations, plus all of its
            # translations, minus myself.
            return self.__class__().objects.filter(
                Q(pk=self.translation_of.pk) |
                Q(translation_of=self.translation_of.pk)).exclude(pk = self.pk)

    def get_translation(self, language):
        """Return a specific translation of this page."""
        if self.language == language:
            return self
        # If I am the root translation, search for translations of me in the given language
        elif self.translation_of is None:
            try:
                return self.translation_set.get(translation_of=self.id, language=language)
            except self.DoesNotExist:
                return None
        # Find the root page and the specific translation
        else:
            # If am not the root, find the root page with the given language,
            # otherwise find the page that is a translation of me in the given language
            return TranslatableModelMixin.objects.filter(
                models.Q(id=self.translation_of.id) |
                models.Q(translation_of=self.translation_of.id),
                language=language)


    class Meta:
        abstract = True