Article:
  actAs:
    Timestampable: ~
    I18n:
      fields: [ title, body ]
      actAs:
        Sluggable: { fields: [ title ], uniqueBy: [ lang, title ] }
 
  columns:
    title: { type: string(255), notnull: true }
    body: { type: clob, notnull: true }
    author: { type: string(255), notnull: false }
 
News:
  inheritance:
    extends: Article
    type: concrete

News:
  n1:
    author: 'Lenta.ru'
    Translation:
      ru:
        title: 'Нет вестей с Титана'
        body: |
          Титан – это шестой и самый крупный спутник Сатурна.
 
  n2:
    author: 'Bash.org'
    Translation:
      en:
        title: '#921792'
        body: |
          <Thomas> if women think they arent meant to cook
          <Thomas> why do they have milk and eggs inside them?

php symfony doctrine:build --all --and-load
php symfony generate:app backend
php symfony doctrine:generate-admin backend News

mysql> SELECT * FROM news;
+----+-------------+---------------------+---------------------+
| id | author      | created_at          | updated_at          |
+----+-------------+---------------------+---------------------+
|  1 | Lenta.ru    | 2010-01-29 12:14:46 | 2010-01-29 12:14:46 | 
|  2 | Bash.org    | 2010-01-29 12:14:46 | 2010-01-29 12:14:46 | 
+----+-------------+---------------------+---------------------+
 
mysql> SELECT id, lang, title FROM news_translation;
+----+------+-----------------------------------------------------+
| id | lang | title                                               |
+----+------+-----------------------------------------------------+
|  1 | ru   | Титан – это шестой и самый крупный спутник Сатурна. | 
|  2 | en   | <Thomas> if women think they arent meant to cook ...| 
+----+------+-----------------------------------------------------+

// lib/form/doctrine/NewsForm.class.php
class NewsForm extends BaseNewsForm
{
  /**
   * @see ArticleForm
   */
  public function configure()
  {
    parent::configure();
    $this->embedI18n(array('ru', 'en'));
  }
}

# config/app.yml
all:
  cultures:
    enabled:
      ru: Russian
      en: English

// lib/form/doctrine/NewsForm.class.php
 
// Revert the changes we added there
class NewsForm extends BaseNewsForm
{
  /**
   * @see ArticleForm
   */
  public function configure()
  {
    parent::configure();
  }
}
 
// lib/form/doctrine/ArticleForm.class.php
class ArticleForm extends BaseArticleForm
{
  /**
   * Available languages
   *
   * @var array $languages
   **/
  protected $langages;
 
  public function configure()
  {
    $this->languages = sfConfig::get('app_cultures_enabled');
 
    $langs = array_keys($this->languages);
 
    $this->embedI18n($langs);
    foreach($this->languages as $lang => $label)
    {
      $this->widgetSchema[$lang]->setLabel($label);
    }
  }
}

// lib/form/doctrine/ArticleForm.class.php
class ArticleForm extends BaseArticleForm
{
  /**
   * Available languages
   *
   * @var array $languages
   **/
  protected $langages;
 
  public function configure()
  {
    $this->languages = sfConfig::get('app_cultures_enabled');
 
    $langs = array_keys($this->languages);
 
    $this->embedI18n($langs);
    foreach($this->languages as $lang => $label)
    {
      $this->widgetSchema[$lang]->setLabel($label);
    }
  }
 
  /**
   * Cleans and binds values to the current form
   *
   * Ignore i18n forms when all their fields are empty
   *
   * @see sfForm::doBind
   **/
  protected function doBind(array $values)
  {
    foreach($this->languages as $lang => $label)
    {
      if($this->embeddedI18nFormIsEmpty($values[$lang]))
      {
        unset(
          $values[$lang],
          $this[$lang]
        );
      }
    }
 
    parent::doBind($values);
  }
 
  /**
   * Check if every fields, except for id and lang, are empty
   **/
  protected function embeddedI18nFormIsEmpty(array $values)
  {
    foreach($values as $key => $value)
    {
      if(in_array($key, array('id', 'lang')))
        continue;
 
      if('' !== trim($value))
      {
        return false;
      }
    }
    return true;
  }
}

mysql> SELECT id, lang, slug FROM news_translation;
+----+------+------------------------------------------------------+
| id | lang | slug                                                 |
+----+------+------------------------------------------------------+
|  1 | en   |                                                      | 
|  1 | ru   | Титан – это шестой и самый крупный спутник Сатурна.  | 
|  2 | en   | <Thomas> IF women think they arent meant TO cook ... | 
+----+------+------------------------------------------------------+

// lib/form/doctrine/ArticleForm.class.php
 
  // Add this at the beginnig of the class:
  /**
   * I18n ignored forms
   **/
  protected $I18nFormsIgnored = array();
 
  // update the doBind method:
  /**
   * Unset i18n forms values when every field is empty
   **/
  protected function doBind(array $values)
  {
    foreach($this->languages as $lang => $label)
    {
      if($this->embeddedI18nFormIsEmpty($values[$lang]))
      {
        $this->I18nFormsIgnored[] = $lang;
        unset(
          $values[$lang],
          $this[$lang]
        );
      }
    }
 
    parent::doBind($values);
  }
 
  // And override the doUpdateObject method:
  /**
   * Updates the values of the object with the cleaned up values.
   *
   * @param  array $values An array of values
   *
   * @see sfFormDoctrine::doUpdateObject()
   */
  protected function doUpdateObject($values)
  {
    parent::doUpdateObject($values);
 
    foreach($this->I18nFormsIgnored as $lang)
    {
      unset($this->object->Translation[$lang]);
      unset($values[$lang]);
    }
  }