Drupal - Migration - Add term reference, included in a field collection, to an entity from CSV data

my_data.csv

"id","user","language_name"
1,"username","English"
....
....

MyMigration.inc

class MyMigration extends MyBaseMigration {

  public function __construct(array $arguments) {
    parent::__construct($arguments);

    // Description.
    $this->description = t('Description');

    // Dependencies.
    $this->dependencies = array('MyUser');

    // Mapping Table.
    $this->map = new MigrateSQLMap(
      $this->machineName,
      array(
        'id' => array(
          'type' => 'int',
          'not null' => TRUE,
          'description' => 'Source id'
        ),
      ),
      MigrateDestinationFieldCollection::getKeySchema()
    );

    $source_file = drupal_get_path('module', 'my_module') . '/data/my_data.csv';

    $columns = array(
      // [..]
      array('language_name', 'language_name'),
    );

    $this->source = new MigrateSourceCSV(
      $source_file,
      $columns,
      array(
        'header_rows' => 1,
        'delimiter' => ',',
        'enclosure' => '"'
      )
    );

    $this->destination = new MigrateDestinationFieldCollection(
      'my_field_collection_name',
      array('host_entity_type' => 'my_entity')
    );
    

    $this->addFieldMapping('host_entity_id', 'my_entity')->sourceMigration('MyClassThatImportTheEntity');
    $this->addFieldMapping('term_reference_field', 'language_name');
    $this->addFieldMapping('term_reference_field:source_type')->defaultValue('term_name');
    $this->addFieldMapping('term_reference_field:create_term')->defaultValue(TRUE);
    $this->addFieldMapping('term_reference_field:ignore_case')->defaultValue(TRUE);
    
  }
}