public function offsetGet( $offset )
    {
        // This needs to check if this language can be instanciated (e.g. is active on the installation)
        if ( !isset( $this->childrenFieldSets[$offset] ) )
        {
            throw new Exception( "Language $offset could not be found on this ezpContent" );
        }

        return $this->childrenFieldSets[$offset];
    }