Migrate drupal to drupal doesn't work

I'm creating some D7 to D7 migrate imports, i've mapped the fields like this:

class MigrazioneNodiConcept extends MigrazioneNodi{
  public function __construct(array $arguments) {
    parent::__construct($arguments);

    $this->sourceFields['title_field:language'] = 'Titolo: lingua del campo';
    $this->sourceFields['field_subtitle_concept:language'] = 'Subtitle: lingua del campo';

    $this->source = new MigrateSourceSQL($this->query(), $this->sourceFields, NULL, $this->sourceOptions);

    $this->addFieldMapping('title_field', 'title_field');
    $this->addFieldMapping('title_field:language', 'title_field:language');

but nothing appens. All the fields are imported with one (random) language... all my modules are in the latest DEV version... someone can help me?