The concept of an 'artificial language' such as Esperanto may seem odd to some of us, but it can't be disputed that many people are enthusiastic speakers of such languages. We talk with two experts who presented at this year's Lingua Fest event which took place in Bratislava in September. You may never heard of 'mitochondria' but you can't live without them - tiny 'organelles' that form an integral part of the structure of our living cells. We speak with a scientist and mitochondria researcher at September's Európska noc výskumníkov event held in Bratislava.